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1.
Participatory plant breeding with maize in Mexico and Honduras 总被引：2，自引：1，他引：2
Maize is a staple food crop in many developing countries. However, if seven major maize producing countries are excluded from
this group, data indicate that only 34% of the maize area is planted with improved seed despite considerable effort invested
in maize breeding. This has led researchers to investigate other options, such as farmer-participatory plant breeding, for
delivering the benefits of plant breeding knowledge and technology to farmers in developing countries. This paper describes
short-term results from participatory maize breeding studies in Mexico and Honduras. Results from three selection cycles in
Mexico suggest that stratified mass selection without pollination control, with selections carried out by researchers in farmers'
fields, may be effective at improving yield in farmers' local varieties. In Honduras, mass selection with pollination control,
where selections were done by collaborating farmers in their own fields on their own varieties, showed trends (non-significant)
towards yield improvement. Farmer selection seemed to offer the greatest yield benefit over experiment station selection on
the farm with the lowest yield potential, suggesting that farmer-participatory approaches may be most advantageous in marginal
environments where experiment station conditions differ most dramatically from farmers' conditions. These studies highlighted
the importance of seed systems knowledge in designing participatory plant breeding programs. For cross-pollinated crops, they
also highlighted the need to balance progress from selection and demands on farmers' time and labor in choosing breeding methods.
Further work is needed to investigate farmer-participatory breeding approaches that can address post-harvest traits.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
Formal plant breeders could contribute much to collaboration with farmers for improving crop varieties for local use. To do
so outside researchers must have some understanding of local selection practices and their impact on crop populations in terms
of the genetic theory underlying plant breeding. In this research we integrated methods from social and biological sciences
to better understand selection and its consequences from farmers' perspectives but based on the concepts used by plant breeders.
Among the households we worked with, farmers' selection practices were not always effective yet they understood the reasons
for this and had no expectations for response to selection in some traits given the methods available to them. Farmers' statements,
practices and genetic perceptions regarding selection and the genetic response of their maize populations to their selection
indicate selection objectives different than may be typically assumed, suggesting a role for plant breeder collaboration with
farmers.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
B. Courtois B. Bartholome D. Chaudhary G. McLaren C.H. Misra N.P. Mandal S. Pandey T. Paris C. Piggin K. Prasad A.T. Roy R.K. Sahu V.N. Sahu S. Sarkarung S.K. Sharma A. Singh H.N. Singh O.N. Singh N.K. Singh R.K. Singh R.K. Singh S. Singh P.K. Sinha B.V.S. Sisodia R. Takhur 《Euphytica》2001,122(3):537-550
A number of breeding institutions developed a project to assess importance of participatory plant breeding approaches for
rainfed rice improvement in eastern India. The results of the first two years of participatory varietal selection are reported
here. The objective was to evaluate the respective effects of participation of farmers in varietal evaluation and decentralization
of varietal testing from breeding stations to farmers' fields on varietal ranking. Fields representing various hydrological
situations were chosen in two to three villages at four rainfed lowland sites and one upland site. Sets of 15 to 25 varieties
were tested both in farmers' fields and on-station in 1997 and 1998 and ranked by both farmers and breeders. The effect of
participation was judged by comparing the rankings attributed by farmers and breeders to a given set of material in a given
trial. The effect of decentralization was determined through comparisons between individual breeders' rankings across trials.
Farmers' rankings were not randomly allocated, but agreement within the farmers' group was not always very strong. Except
at one site, concordance among breeders' ranking was high, but, because of the limited number of breeders involved, it was
seldom significant. In about two-thirds of the trials, there was a good agreement between farmers' and breeders' mean rankings.
The consensus was particularly strong when severe constraints induced contrasting behavior in the genotypes. The decentralization
effect appeared to be moderate, but variations due to a breeder effect were recorded. The part of genotype by environment
interactions for grain yield due to location within one site and year was evaluated through various methods, showing more
effect of G × E interactions at some sites than at others. Crossover interactions inducing changes in ranks represented a
limited part of the yearly G × E interactions at all sites. Both farmer participation and decentralization of varietal testing
in farmers' field would help in best matching the varieties to the needs, although their combined contribution would be more
useful in some sites than in others.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
S. Ceccarelli S. Grando M. Singh M. Michael A. Shikho M. Al Issa A. Al Saleh G. Kaleonjy S.M. Al Ghanem A.L. Al Hasan H. Dalla S. Basha T. Basha 《Euphytica》2003,133(2):185-200
Farmer participation is increasingly seen as a key to develop technologies which are more relevant to farmers' communities.
In plant breeding, farmer participation is seen as key to increase the probability of adoption of new varieties. This paper
addresses the issue of selection efficiency in participatory plant breeding by testing the effect of selection environment
and of who did the selection in one cropping season (1997) on the performance of the selected lines in the following cropping
season (1998). Selection environment had a larger effect on response to selection than who did the selection, confirming the
importance of decentralized selection. Selections made by the breeder and the farmers in 1997, differed in 1998 for a number
of traits, but seldom for grain yield. When the difference for grain yield was significant, breeder's selection was more effective
on station, while farmers' selection was more effective in farmers' fields. The results of this study indicate that it is
possible to organize a plant breeding program with the objective of adapting crops to a multitude of both physical and socio-economic
environments: such a breeding program will, at the same time, increase productivity and stability, enhance biodiversity and
produce environmentally friendly cultivars.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
This paper describes how plant breeders and farmers worked together to produce improved varieties of maize for the low-resource
farmers of the Panchmahals district of Gujarat, India. Initially, farmers tested a range of maize varieties in a participatory
varietal selection (PVS) programme. However, none of these proved to be very popular with farmers, although farmers who had
more fertile fields adopted the variety Shweta from Uttar Pradesh. Hence, in 1994 a participatory plant breeding (PPB)programme
was begun to generate new, more appropriate varieties. Yellow- and white-endospermed maize varieties were crossed that had
been either adopted to some extent following PVS or had attributes, such as very early maturity,that farmers had said were
desirable. In subsequent generations, the population was improved by mass selection for traits identified by farmers. In some
generations,farmers did this in populations which were grown by breeders on land rented from a farmer. Soil fertility management
was lower than that normally used on the research-station. The breeding programme produced several varieties that have performed
well in research-station and on-farm trials. One of them, GDRM-187, has been officially released as GM-6 for cultivation in
hill areas of Gujarat state,India. It yielded 18% more than the local control in research-station trials, while being seven
days earlier to silk. In farmers' fields, where average yields were lower, the yield advantage was 28% and farmers perceived
GDRM-187 to have better grain quality than local landraces. PPB produced a variety that was earlier to mature than any of
those produced by conventional maize breeding, and took fewer years to do so. The returns from PPB,compared to conventional
breeding, are higher because it is cheaper and benefits to farmers are realised earlier.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally
adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers
participated in the selection of advanced materials, rather than finished cultivars. This paper describes this approach and
reports experiences with farmers–breeders collaboration.
As breeders involved farmers as participants, they learned more about the most important criteria of male and female farmers
for preferred cultivars in the marginal environments of Andean cropping systems. This approach encouraged the use of locally
adapted cultivars (often landraces), made the breeders less dependent on foreign materials, and has resulted in selection
and development of new wheat, barley, common bean, quinoa, potato and maize cultivars.
Breeding programmes based on crossing locally adapted cultivars followed by selection by the breeders in the early phases
of the breeding programmes and by participatory selection with the farmers in the more advanced stages of the breeding programmes
appeared successful. It became clear that breeders must be well acquainted with the farmer preferences such as the requirements
for specific agronomic, storage, processing and marketing traits.
Over a period of five years the centralized formal breeding approach predominantly based on material produced by the international
institutes was replaced by decentralized breeding approaches based largely on local germplasm with extensive farmer participation. 相似文献
7.
Summary The evaluation aimed at identifying landrace genotypes adapted to the rather unfavourable growing conditions of durum wheat in Sicily, to be used as parental material in a breeding programme. The trial was carried out in three seasons experiencing varying climatic conditions, and included 75 landraces, 25 of which were selected under severe drought in Syria. Wide differences were observed for most traits among genotypes and seasons of evaluation. Yields of the best performing entries identified in each season never significantly differed from that of the best check variety. The top-yielding landraces were consistently better than the remaining entries for the three yield components, viz. number of spikes per plant, number of kernels per spike and mean kernel weight. In the driest season they were also significantly earlier in heading, confirming the importance of earliness under drought. An analytical breeding approach relying on an array of morpho-physiological traits as selection criteria did not seem appropriate for the given environment, as the variable stress level enhanced the importance of specific traits under specific situations. The genotypic response was largely season-specific. Nonetheless, five landraces were in the best group in all seasons. The selection made in Syria also appeared somewhat effective in Sicily, particularly in the less favourable seasons. 相似文献
8.
Experimental results and farmer surveys from a Mexican community located in the buffer zone of a biosphere reserve indicate
that farmers' seed selection practices protect the phenological integrity of their traditional maize varieties as they define
them, despite numerous factors contributing to genetic instability. Analysis of morphological and genetic data suggests that
when subjected to significant gene flow through cross-pollination, ear characteristics are maintained through farmers' selection
even though other characteristics may continue to evolve. Because the effects of farmers' selection practices are confined
largely to ear characteristics, their practices appear to offer only limited scope for variety improvement. Farmers' expectations
of what they can achieve through seed selection are similarly limited. These findings suggest complementary roles for professional
breeders and Mexican farmers in enhancing mass selection methods to improve maize landraces on farms – if farmers themselves
perceive benefits from the collaboration.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
A. M. Osman C. J. M. Almekinders P. C. Struik E. T. Lammerts van Bueren 《Euphytica》2008,163(3):511-522
Main stream commercial onion breeders do not select varieties for organic farming, but solely for conventional farming. Seed
companies consider the organic market too small to justify investments in breeding for this sector. In order to study if their
varieties also suit organic farmers’ needs we interviewed four Dutch commercial onion breeders on their breeding programme
and selection criteria and compared the outcome with a variety profile composed of the priority traits of Dutch organic farmers.
Breeders gave priority to the same storage and bulb quality traits that are demanded by organic farmers, because organic onions
are exported to conventional supermarkets that apply the same quality standards to organic and conventional onions. However,
organic farmers also need varieties that perform well in the field. Breeders give low priority to field selection. Furthermore,
three of the four seed companies only breed hybrids. The cytoplasmic male sterility system used to produce these hybrids does
not comply with organic principles. We conclude that at present breeders can provide varieties that meet organic farmers’
demands for storability and quality traits, but they should give higher priority to field selection to also improve required
field traits. The latter will only occur, if in future the organic seed market will grow. If the organic sector wants varieties
developed according to its own principles, it should either set up its own onion breeding programme or seek alliances with
breeding companies that are prepared to harmonize their breeding methodology with the organic principles. 相似文献
10.
A. Efisue P. Tongoona J. Derera A. Langyintuo M. Laing B. Ubi 《Journal of Agronomy and Crop Science》2008,194(5):393-400
Rice is an important staple food and cash crop. Although many varieties of rice have been developed to date, few are adopted possibly because researchers did not take into account farmers’ preferences and perceptions on varieties during the development process. Because farmers increasingly rely on low-yielding landraces, production fails to meet demand. To provide an understanding of farmers’ preferences for rice cultivars and perceptions on drought stress and management practices as inputs to rice breeding research, this study was conducted in the Sikasso region of Mali in September 2005 using participatory rural appraisal approach. A total number of 125 farmers were randomly selected from 10 villages in three ecologies and interviewed individually and in groups. Results showed that farmers’ preferences, crop management practices and ranking of production constraints differed significantly across ecologies. Whereas farmers in the irrigated ecologies preferred high-yielding, long duration rice varieties, those in the upland and lowland ecologies preferred tall plants of short duration. While upland and lowland farmers preferred red and white long grains, respectively, irrigated ecologies were indifferent about grain colour. Farmers appeared willing to trade-off yield for grain quality and plant height, inconsistent with traditional breeders’ selection criteria. The high preference for tall varieties among farmers in the upland and lowland ecologies also contrasted sharply with the model of dwarf rice varieties responsible for the green revolution in Asia. The implication of these findings for rice breeders is that different plant idiotypes complemented by effective drought management practices should target different ecologies to increase impact. 相似文献
11.
Despite the presence of large numbers of improved maize cultivars, farmers in the Hararghe highlands of eastern Ethiopia persistently
grow local cultivars and are not benefiting from the varietal improvement program. By growing local cultivars farmers obtain
an average yield of 1.2 t -1 whereas research has released cultivars yielding 5–11 t -1under on-station conditions. Recognizing this and the important role maize is playing in the livelihood system of farmers
in eastern Ethiopia; Participatory Varietal Selection (PVS) was conducted for three consecutive seasons (1996–1998) in three
locations. The objectives of the study were to identify farmers' cultivar selection criteria for future breeding, to enable
farmers to assess the performance of improved cultivars under their management, to increase farmers' access to the cultivars
of their preference by injecting source seed into the local seed system, and to investigate whether breeding for wide adaptation
like for the Hararghe highlands has any drawbacks or not. The study indicated farmers' maize varietal selection criteria together
with the differences in selection criteria across locations classified under the same adaptation zone. Though farmers selected
some of the many improved cultivars tested, no improved cultivar had all the characteristics, which farmers want in a single
cultivar. To be able to combine cultivar selection traits farmers considered cultivar combinations in all locations, but not
the single `best' cultivar. Despite the yield advantage of hybrids, farmers selected Open Pollinated Varieties (OPVs) because they had more
preferred traits. Farmers also preferred to retain their local cultivars despite their lower yield compared to most of the
improved cultivars. Both situations confirmed how resource poor farmers' cultivar requirements are much more diverse than
yield per se. Gender and social group-driven difference in cultivar preference was also observed. The study revealed the need
for proper zoning of the Hararghe highlands as a prerequisite to developing better adapted maize cultivars to the varied agro
ecological and socioeconomic niches. As shown in this study, proper zoning, due consideration to farmers' relevant selection
traits and wider use of participatory approaches should be adapted to develop cultivars which can gain farmers acceptance.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
It is widely recognized that conventional plant breeding has been more beneficial to farmers in high-potential environments
or those who can profitably modify their environment to suit new cultivars, than to the poorest farmers who cannot afford
to modify their environment through the application of additional inputs and cannot risk the replacement of their traditional,
well known and reliable varieties. As a consequence, low yields, crop failures, malnutrition, famine, and eventually poverty
still affect a large proportion of humanity. Participatory plant breeding (PPB) is seen by several scientists as a way to
overcome the limitations of conventional breeding by offering farmers the possibility to choose, in their own environment,
which varieties suit better their needs and conditions. PPB exploits the potential gains of breeding for specific adaptation
through decentralized selection, defined as selection in the target environment, and is the ultimate conceptual consequence
of a positive interpretation of genotype × environment interactions. The paper describes a model of PPB developed by The International
Center for Agricultural Research in the Dry Areas and used successfully in several countries in West Asia and North Africa.
Genetic variability is generated by breeders, selection is conducted jointly by breeders, farmers, and extension specialists
in a number of target environments, and the best selections are used in further cycles of recombination and selection. Technically,
the process is similar to conventional breeding, with three main differences. Testing and selection take place on-farm rather
than on-station, key decisions are taken jointly by farmers and the breeder, and the process can be independently implemented
at a large number of locations. The model also incorporates seed production. Farmers handle the initial phases, multiplying
promising breeding material in village-based seed production systems. The PPB model is flexible; it can generate populations,
pure lines, and eventually mixtures of pure lines in self-pollinated crops; as well as hybrids, populations, and synthetics
in cross-pollinated crops. PPB has several advantages. New varieties reach the release phase much faster than in conventional
breeding, and are better suited to farmers’ needs and willingness to invest in inputs and management. Release and seed multiplication
activities concentrate on varieties known to be farmer-acceptable. These advantages are particularly relevant to developing
countries where large investments in plant breeding have not yielded returns, and many “improved” varieties developed through
conventional breeding are not adopted by farmers. PPB also ensures that biodiversity is maintained or increased because different
varieties are selected at different locations. In addition to the economical benefits, participatory research has a number
of psychological, moral, and ethical benefits, which are the consequence of a progressive empowerment of the farmers’ communities;
these benefits affect sectors of their life beyond the agricultural aspects. In conclusion, PPB, as a case of demand driven
research, gives voice to farmers, including those who have been traditionally the most marginalized such as the women, and
elevates local knowledge to the role of science. 相似文献
13.
Pearl millet (Pennisetum glaucum [L.]R.Br.) is the staple food and fodder crop of farmers in the semi-arid areas of north-west India. The majority of farmer
sin western Rajasthan depend on their own seed production and employ different seed production strategies that involve different
levels of modern-variety introgression into landraces as well as different selection methods. This study quantifies the effects
of three seed management strategies on environmental adaptation and trait performance. Forty-eight entries representing farmers’
grain stocks — pure landraces or landraces with introgressed germ plasm from modern varieties — as well as 33 modern varieties,
multiplied by breeders or farmers, were evaluated in field trials at three different locations over two years under varying
drought-stress conditions. Results indicate that the plant characteristics employed by farmers in describing adaptive value
and productivity is an effective approach in discriminating the type of millet adapted to stress and non-stress conditions.
It was also found that introgression of modern varieties(MVs) leads to populations with a broader adaptation ability in comparison
to pure landraces or MVs alone – but only if MV introgression is practised regularly and is combined with mass panicle selection.
Under high-rainfall conditions, farmer grain stocks with MV introgression show similar productivity levels as modern varieties.
Under lessening rainfall, pure landraces show, in tendency, higher grain yields. In conclusion, farmers’ seed management could
form an integral part of participatory breeding programs.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Maria Jose de Oliveira Zimmermann 《Euphytica》1996,92(1-2):129-134
Summary Despite the growing industrialization, technification and transformation that is happening in the agriculture around the world, and despite that agricultural research has always concentrated its effort on sole crops, multiple cropping systems have historically been important for common bean production in tropical countries. The reasons for this fact, are economical and social, as well as biological. Bean breeders have always been questioned on their work, because the development of new varieties is usually done in sole crop, but the varieties are grown in either systems. This paper addresses a set of questions that are usually presented to the breeders, in light of the evidence obtained from many trials conducted in Brazil and in the U.S.A.: Will the genotypes bred for sole crop conditions, perform well when grown in intercrop; How different should a genotype be, for cultivation in intercropping compared to genotypes developed for sole crop conditions; Is there a need for special breeding programs for intercropping and How could a breeding program focus the question of multiple (associated) cropping? 相似文献
15.
Changes in allele type, allele frequency and genetic diversity because of selection by individual farmers and breeders were assessed using simple sequence repeats (SSRs) during one cycle of selection in a decentralized participatory barley breeding programme. Selection by both breeders and farmers resulted in the loss of a number of alleles in the majority of the locations, with more alleles lost in the heterogeneous breeding materials than in the fixed genotypes, indicating selection against undesirable traits uncovered in the heterogeneous breeding materials that are presumably linked to SSR alleles. After selection, significant allelic frequency changes were observed at several loci in both the germplasm groups. As the selection was conducted independently in each location, an allele had a chance of being selected in more than one location, and therefore considering the whole study area the allelic composition and diversity of the original genetic materials was maintained after the selection. The study showed the importance of decentralized participatory plant breeding in maintaining genetic diversity that helps stabilize and sustain production in unpredictable production conditions. 相似文献
16.
John E. Bradshaw 《Euphytica》2017,213(3):60
Plant breeders can help farmers increase food production by breeding new cultivars better adapted to their chosen farming systems, but these must be capable of providing the necessary plant inputs for the required levels of crop production in 2050. Until 200 years ago the farmers themselves were the plant selectors. Plant domestications, extensive crop dispersions and farmers’ selections produced thousands of locally adapted landraces of cultivated plants. During the twentieth century these were largely replaced by relatively few high yielding cultivars and the natural habitats of many of their wild relatives became endangered. Hence in situ and ex situ conservation, and evaluation and use of plant genetic resources is vital for future plant breeding. The development of scientific breeding from the beginning of the twentieth century was based on understanding the mechanism of inheritance and the mating systems of crop plants. The types of genetically uniform, high yielding cultivars that have been bred from genetically heterogeneous landraces were determined by the mode of reproduction and mating system of the cultivated plant species: inbred line (wheat) and hybrid (rice) cultivars for inbreeding species, hybrid (maize) cultivars for outbreeding species, and clonal (potato) cultivars for vegetatively propagated species. When genetically heterogeneous crops are desired, mixtures of cultivars and synthetic cultivars can be produced. Future progress in crop improvement will come from three complementary approaches: use of hybridization and selection in further conventional breeding, base broadening and introgression; mutation breeding, cisgenesis and gene editing; and genetically modified crops. 相似文献
17.
The cost of participatory barley breeding 总被引：2，自引：0，他引：2
Farmer participation in agricultural research is increasingly seen as a powerful methodology to increase the relevance of technologies developed to benefit farmers' communities. In plant breeding, farmer participation is considered as a way to increase the probability of adoption of new varieties. However, the higher expected cost of participatory plant breeding (PPB) is seen as one of the main obstacles to its wider adoption.This paper addresses the issue of the different costs to an Institution of running a PPB program or a non-participatory program and uses the barley-breeding program at the International Center for Agricultural Research in the Dry Areas (ICARDA) as a case study.Observations and data collection were carried out during one full cropping season on the cost of the three main components of the breeding program, i.e. the management of the field trials (land and seedbed preparation, planting, fertilizer application, weed control, harvesting, and seed threshing, cleaning, treating and packaging), the travel to farmers' fields or to the research sites, and the human resources (scientists, technical staff, local workers and farmers) involved in breeding activities.We compared two options for the centralized–non-participatory breeding program, differing in the number of sites (8 and 16) used for the on-farm trials, with 160 options for the decentralized-participatory breeding program, differing in the combination of number of sites (from 4 to 16) and number of trials per site (from 1 to 10).The results show that in both decentralized-participatory and centralized–non-participatory plant breeding the cost of managing the field trials is the highest followed by the cost of human resources and that of travel: the contribution of each component to the total cost varies with the various options and the various combinations of the number of sites and of farmers.The comparison of the aggregated costs indicates that in the case of the ICARDA' barley-breeding program there are no relevant differences between the participatory and the non-participatory plant breeding programs. This is largely associated with the fact that the decentralized-participatory breeding program reaches the same level of development of the breeding material 3 years earlier than the centralized–non-participatory breeding program. Depending on the type of centralized-breeding program and on the combination of number of sites and number of farmers per site in the participatory program, the aggregated costs of the participatory program are lower than those of the centralized-breeding program by between 5 and 28%. At the same level of cost of the centralized program, the model of participatory program used in this study generates more information due to the use of more trials at each site. This improves selection efficiency and provides an analytical tool to optimize the number of sites and of farmers per site. 相似文献
18.
Summary A method of testing spaced plants in swards of another grass crop is described. The procedure provides information on sward performance at each stage of the breeding scheme. A large number of entries may be included, together with whatever cutting frequency.When used for perennial ryegrass, the method favours the selection of productive and persistent plants. 相似文献
19.
Summary Over 7,600 durum wheat accessions belonging to 22 country gene pools were evaluated in Syria, during the seasons 1985–86 through 1987–88 under semi-arid Mediterranean climatic conditions. Data on seven agronomic traits are presented to assess the distinctiveness and the phenotypic diversity of these pools. Univariate statistical analysis revealed differences among materials of diverse origins for all traits. Mean phenotypic diversity within countries was highest in the germplasm from India, lowest in that from Bulgaria. In a canonical variate analysis, the first three canonical variables explained 77.7% of the total variance. A cluster analysis was performed to supplement the generated information by the canonical analysis. The multivariate analyses evidenced the distinctiveness of the Ethiopian germplasm. The gene pools from Syria and Jordan, closely resembling each other, appeared separate from all others. A certain peculiarity was also shown by the germplasms from Greece, Morocco and France, while the remaining countries clustered into four groups. The results of the present evaluation could provide useful information for breeding activities, germplasm collection, and establishment of core collections. Evidence is presented that environment played a major role in creating the overall variation for the considered traits, although germplasm exchange seemed also an important factor. 相似文献
20.
Summary Differences in development of the apex may be the reason for cultivar differences in adaptation of barley to terminal drought in Mediterranean environments. The present study was conducted to identify apical development patterns of barley adapted to terminal drought stressed Mediterranean environments and to determine plant characteristics which can be used as criteria to select for an adapted development. Thirty-five two-rowed barley (Hordeum vulgare L.) entries were grown at two sites in northern Syria (Tel Hadya and Breda) in 1988/89. Four apical development patterns were observed: a slow or fast vegetative development, depending on the vernalization requirement, combined with a slow or fast generative development, depending on the daylength response of the crop. Early heading was related to fast generative development. Leaf appearance rates on the main shoot were constant during a major part of the pre-anthesis period, but significant differences were observed among development patterns. Genotypic differences in main shoot tiller number were associated with differences in the onset of tiller appearance and not with differences in tiller appearance rate or final leaf number on the main shoot. Since vernalization requirements and daylength responses are largely independent of terminal drought stress, selection for an adapted phenology can be done in favourable environments. Morphological traits related to these responses (winter growth habit, cold tolerance, plant colour, growth vigour, heading date) can be used as criteria for selection for adaptation to low-rainfall Mediterranean environments. 相似文献