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1.
Summary Groups of 10 barley genotypes were selected for high grain yield under either high yielding (two groups) or low yielding conditions (two groups). The genotypes had a similar average grain yield across a wide range of yielding conditions, but differed in their linear response over environments (environmental sensitivity). The genotypes selected for high grain yield under low yielding conditions were less sensitive to changing environments than genotypes selected for high grain yield under high yielding conditions. The higher stability of genotypes selected under low yielding conditions was shown by both the linear regression analysis and the comparison of coefficients of variation. The use of a safety-first index showed that the probability of a crop failure of genotypes selected for high grain yield under high yielding conditions was between 1.8 and 2.7 times higher than for genotypes selected for high grain yield under low yielding conditions. The development of new cultivars for areas where a large proportion of the crop is grown by subsistence farmers should therefore be based on selection under low yielding conditions. 相似文献
2.
Durum wheat is grown in the Mediterranean region under stressful and variable environmental conditions. In a 4-year-long experiment,
14 genotypes [including 11 durum breeding lines, two durum (Zardak) and bread (Sardari) wheat landraces, and one durum (Saji)
newly released variety] were evaluated under rainfed and irrigated conditions in Iran. Several selection indices [i.e. stress
tolerance index (STI), drought tolerance efficiency (DTE), and irrigation efficiency (IE)] were used to characterize genotypic
differences in response to drought. The GGE biplot methodology was applied to analyze a three-way genotype-environment-trait
data. Combined ANOVA showed that the year effect was a predominant source of variation. The genotypes differed significantly
(P < 0.01) in grain yield in the both rainfed and irrigated conditions. Graphic analysis of the relationship among the selection
indices indicated that they are not correlated in ranking of genotypes. The two wheat landraces and the durum-improved variety
with high DTE had minimum yield reduction under drought-stressed environments. According to STI, which combines yield potential
and drought tolerance, the “Saji” cultivar followed by some breeding lines (G11, G8, and G4) performed better than the two
landraces and were found to be stable and high-yielding genotypes in drought-prone rainfed environments. The breeding lines
G8, G6, G4, and G9 were the efficient genotypes responding to irrigation utilization. In conclusion, the identification of
the durum genotypes (G12, G11, and G4) with high yield and stability performance under unpredictable environments and high
tolerance to drought stress conditions can help breeding programs and eventually contribute to increasing and sustainability
of durum production in the unpredictable conditions of Iran. 相似文献
3.
Decentralized selection and participatory approaches in plant breeding for low-input systems 总被引：1，自引：0，他引：1
Heterogeneous environments make it difficult to apply consistent selection pressure because often it is difficult to identify
a single or a few superior genotypes across all sets of conditions. However, when the target system is characterized by heterogeneity
of environmental stress, varieties developed in high-yielding conditions may fail to satisfy farmers’ needs. Although this
type of system is often found in marginal environments of developing countries, heterogeneous environmental conditions are
also a feature of organic and low-external-input systems in developed countries. To meet the needs of these systems, breeding
programs must decentralize selection, and although decentralized selection can be done in formal breeding programs, it is
more efficient to involve farmers in the selection and testing of early generation materials. Breeding within these target
systems is challenging, both genetically and logistically, but can identify varieties that are adapted to farming systems
in marginal environments or that use very few external inputs. A great deal has been published in recent years on the need
for local adaptation and participatory plant breeding; this article reviews and synthesizes that literature. 相似文献
4.
Adaptation to low/high input cultivation 总被引：1，自引：0，他引：1
Salvatore Ceccarelli 《Euphytica》1996,92(1-2):203-214
Summary Many aeas of world, particular those where agriculture is largely practiced by resource-poor farmers with little or no use of external inputs, have not benefitted from the spectacular yield increases achieved by the combination of modern breeding technologies and use of inputs. The paper argues that because breeding is mostly conducted in presence of high inputs, it has systematically missed the opportunity to exploit genetic differences at low levels of inputs. Many studies show that these differences do exist, particularly in the case of fertilizers, and that these differences can only be identified is selection is conducted under the target level of inputs. Although this was predicted by theory more than 40 years ago, and has been supported by a large body of experimental data, very few breeders select in sub-optimal or stress conditions. The most common justification is the high environmental variation, and hence the lower heritability expected in low input conditions. While this is not supported by experimental evidence, the paper shows that in the case of a typical crop grown in low-input and climatically marginal conditions such as barley, genetic gains are possible by using locally adapted germplasm and by selecting in the target environment. Similar conclusions, in relation to the use of a low-input selection environment, have been reached recently in maize. It is concluded that the best avenue to a sustainable increase of agricultural production in low-input agricultural systems is through locally based breeding programs. 相似文献
5.
Summary Relationships that exist among grain yielding ability and response and stability of grain yields when tested over variable environments were examined. Two sets of oats lines were tested over many environments that had wide ranges in productivities. The lines in each set were divided into high-, medium-, and low-yielding groups on the basis of means across all environments, and variance components for genotype × environment interactions and means of regression responses and coefficients of determination were computed for the three yield categories in each set.Mean grain yields for the high-, medium-, and low-yielding groups across both sets of oats lines were 2.7, 2.3, and 1.9 Mg ha-1, respectively. Coefficients of variability for the genotype × environment interaction were 18%, 16%, and 12% for the high-, medium-, and low-yielding categories, respectively. Means for regression responses were 1.22 for the high group, 0.99 for the medium, and 0.78 for the low. Most responses for the high and low groups were significantly different from 1.0. Means for coefficients of contingency were 0.63, 0.56, and 0.51 for the high-, medium-, and lowyielding groups, respectively.There was a positive relationship between mean grain yield and response of grain yield to improving environments. Thus, high yielding lines are also the responsive lines. Our study gave conflicting results about stability of production for the three yield groups. Coefficients of variation for genotype × environment interaction indicated that the high-yielding group was more interactive with environments than were the medium- and low-yielding ones: However, the means for coefficients of contingency indicated that the high yielding group was the most stable.Journal Paper No. J-12128 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project 2447. 相似文献
6.
Summary Four selection strategies were used on four sets of oat lines to select for grain yield. Two of these used uniform environments whereby sequential selection of the high-yielding lines occurred in continuous high- or continuous low-productivity environments. These are referred to as high and low uniform selection strategies, respectively. The other two selection strategies were conducted by sequential selection of the high-yielding lines in alternating high- and low-productivity environments. They are referred to as high and low shuttle selection strategies, respectively, with high and low designating the productivity of the first environment in the sequence. After three or four cycles of selection, the surviving lines and a random sample from each set were evaluated for mean grain yield, grain yield response to improving environments, and stability of grain yield, in a range of environments typical of oat production on Iowa farms.Grain yield and regression response for all selection strategies, when calculated across all sets of lines, were significantly greater than corresponding values for random samples. Stability was unchanged. The uniform-high and uniform-low strategies gave the greatest and the smallest gains in mean grain yield, respectively, with the shuttle strategies giving intermediate gains. Shuttle selection in predominantly high-productivity environments increased grain yield more than shuttle selection in predominantly low-productivity environments. The uniform-strategy followed by the shuttle-high strategy identified entries with superior performance in high productivity environments. Increased gain in mean grain yield across all environments was associated with increased number of selection cycles conducted in high-productivity environments.Journal Paper No. J-15252 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, Iowa 50011, USA. Project No. 2447. 相似文献
7.
A. G. Balkema-Boomstra 《Euphytica》1992,65(2):99-106
Summary The objective of this study was to evaluate traits which can facilitate and improve selection for grain yield of spring barley. Five experiments were conducted in different environments to measure grain yield and yield related traits of breeding lines and exotic varieties. Differences for rate of canopy expansion were significant and offer the opportunity to select for a high weed suppressing potential but there was no relation to grain yield. Dry matter yield/m2 at anthesis and its water-soluble-carbohydrate content were not correlated with grain yield/m2 and number of grains/m2. Variation in biomass among breeding lines with a similar development and plant height was small. Biomass standardized for plant height was stable across environments and showed a good correlation with number of grains and grain yield. The contribution of pre-anthesis assimilation to grain yield was only important under low yielding experimental conditions, but the differences among the genotypes for this trait were inconsistent. It may be difficult to select genotypes with a high potential contribution of pre-anthesis assimilation to grain yield. 相似文献
8.
John Hamblin 《Euphytica》1977,26(1):157-168
Summary The effect of bulk breeding on yield and its components was studied in two high-yielding and two low-yielding bean crosses until the F6 generation. It was found that bulk breeding on the whole did not alter the mean values in the high-yielding crosses, but that there was a steady increase in the mean values of the low-yielding crosses with generation. As well as mean values the use of variance as a determinant of cross potential was also studied. It was found for characters markedly influenced in their expression by the environment, of which grain yield is the prime example, that progeny variance did not differ significantly from parental variance. It was concluded that interplant competition was the factor of the environment responsible for this effect. 相似文献
9.
Summary The objectives of this research were to study the association in bread wheat between spectral reflectance indices (SRIs) and grain yield, estimate their heritability, and correlated response to selection (CR) for grain yield estimated from SRIs under reduced irrigation conditions. Reflectance was measured at three different growth stages (booting, heading and grainfilling) and five SRIs were calculated, namely normalized difference vegetation index (NDVI), simple ratio (SR), water index (WI), normalized water index-1 (NWI-1), and normalized water index-2 (NWI-2). Three field experiments were conducted (each with 30 advanced lines) in three different years. Two reduced irrigation environments were created: (1) one-irrigation level (pre-planting), and (2) two-irrigation level (pre-planting and at booting stage), both representing levels of reduced moisture. Maximum yield levels in the experimental zone were generally obtained with 4–6 irrigations. Genotypic variations for all SRIs were significant. Three NIR (near infrared radiation) based indices (WI, NWI-1, and NWI-2) gave the highest level of association (both phenotypic and genotypic) with grain yield under both reduced irrigation environments. Use of the mean SRI values averaged over growth stages and the progressive integration of SRIs from booting to grainfilling increased the capacity to explain variation among genotypes for yield under these reduced irrigation conditions. A higher level of broad-sense heritability was found with the two-irrigation environment (0.80) than with the one-irrigation environment (0.63). Overall, 50% to 75% of the 12.5% highest yielding genotypes, and 50% to 87% of the 25% highest yielding genotypes were selected when the NWI-2 index was applied as an indirect selection tool. Strong genetic correlations, moderate to high heritability, a correlated response for grain yield close to direct selection for grain yield, and a very high efficiency of selecting superior genotypes indicate the potential of using these three SRIs in breeding programs for selecting increased genetic gains in grain yield under reduced irrigation conditions. 相似文献
10.
Anne Elings 《Euphytica》1993,70(1-2):85-96
Syrian durum wheat landraces from diverse collection sites were evaluated for agronomic performance under arid conditions over two seasons at four locations, at two levels of nutrient availability.Grain yield differed considerably among locations. Within locations, significant population and fertilizer effects were demonstrated. In most cases, maximum yield was achieved by landraces, which demonstrates the breeding value of local germplasm. In a particular environment, the population effect was nonsignificant for total dry matter production, but significant for straw and grain yield. Nitrogen application was ineffective if moisture availability was the dominant growth limiting factor.Correlations between plant characteristics at evaluation and collection site characteristics were limited, and therefore, their utilization in germplasm evaluation appear limited. The negative relation between grain yield and soil nitrogen content at the collection site may be caused by the comparative disadvantage that germplasm from regions with favourable growing conditions has under low-yielding conditions.Particular environmental conditions at the collection site were no indicator for the response to changed growing conditions. Relatively high grain yields under good and adverse growing conditions excluded each other in all but two cases. Also, it was difficult to relate grain yield to regions of collection, as the response of individual landraces from a certain region to changing growing conditions differed strongly. Differentiation on the basis of landrace groups appears more promising. The Hauran landrace group provided the largest number of populations with relatively high grain yields over diverse environments. 相似文献
11.
Natália Botega Alves Marcio Balestre João Paulo Pennacchi Monique Caroline Nunes Fernandes Douglas Goulart Castro Flávia Barbosa Silva Botelho 《Plant Breeding》2020,139(5):853-861
The rice crop is affected by diseases throughout its cycle, impacting negatively on grain yield and quality. The control of the disease impact can be accomplished via crop breeding, using highly multiple resistant genotypes. This study aimed to evaluate the efficiency of multiple-character and specific selection of multiple resistance to major culture-associated diseases (neck blast, leaf scald and grain discoloration) in rice lines of the Upland Rice Genetic Breeding Program. The experiments were conducted in 35 sites during 12 agricultural years, where 124 lines were evaluated for the severity of fungal diseases, under natural field conditions. Multiple parameters were calculated based on the diseases´ scores: genetic, phenotypic and environmental variances, heritability, selection gain, renewal rate, and genetic and renewal progress. Genetic variance for the disease resistance was identified in the population, and the selection gain for multiple-character selection was of 3.16 year−1 throughout the breeding process with a renewal rate of over 35%. The programme has showed efficiency in selecting multiple resistant genotypes to the mentioned diseases, highlighting genotypes with high potential for market release. 相似文献
12.
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
13.
The presence of genotype × environment (GE) interactions in plant breeding experiments has led to the development of several stability parameters in the past few decades. The present study investigated the repeatability of these parameters for 16 chickpea (Cicer arietinum L.) genotypes by correlating their estimates obtained from extreme subsets of environments within a year and also over years. Based on the estimates of response and stability parameters within each trial, the ranking of genotypes in the low-yielding subset differed from that in the high-yielding subset. This indicates poor repeatability for response and stability parameters over the extreme environmental subsets. The estimates of mean yield and stability parameters represented by ecovalence, W2i, were consistent over years, whereas those of response parameters (bi, and S2i) showed poor repeatability. Our results suggest that single-year results for yield and stability can be used effectively for selecting cultivars with stable grain yield if tested in a wider range of environments. 相似文献
14.
Francis Kwame Padi 《Euphytica》2007,158(1-2):11-25
Twenty-four cowpea genotypes were evaluated under sole cropping or additive series intercropping with sorghum from 2004 to
2005 at four sites representative of the Guinea and Sudan savannah ecologies in Ghana. The aim was to determine whether cowpea
breeding programs that emphasize selection under sole-crop conditions have the potential to produce cultivars that are effective
under additive series intercropping. Genotype × cropping systems interaction was significant for days to 50% flowering but
not for grain yield, biomass and other studied traits. Genotypic yield reaction to cropping systems indicated that bridging
the yield gap between sole cropping and intercropping systems is best addressed by agronomic interventions that reduce stress
on intercrop cowpea rather than by selecting for specifically adapted genotypes for intercropping. Significant genotype × environment
interactions were observed for all traits when data was pooled over cropping systems. Partitioning of the genotype × environment
interaction variance indicated that days to 50% flowering was dominated by heterogeneity of genotypic variance, whereas genotype × environment
interactions for grain yield and biomass was mainly due to imperfect correlations. Large differences in genotypic yield stability
were observed as estimated by the among-environment variance, regression of yield on the environmental index, Kataoka’s index,
and by partitioning of genotype × environment interaction sum of squares into components attributable to each genotype. The
results suggest that in regions where genotype × environment interaction for yield frequently causes re-ranking across environments,
genotypes with the least contribution to the interaction sum of squares are likely to be most productive. On the whole, the
results support the contention that breeding under sole-crop conditions has the potential to produce cultivars effective under
intercropping conditions. 相似文献
15.
Summary Attempts to identify individual traits to use as an indirect measure for grain yield have shown some degree of success in environments where crop yields are affected by no stress or only by predictable stresses. However, analytical breeding has been largely unsuccessful in the case of a) stressful environments characterized by low yields due to high variability in the frequency, timing, duration and severity of a number of climatic stresses, and b) breeding programs where the major objective is greater yield stability defined as a reduction in the frequency of crop failures. Experimental evidence suggests that, when environmental variability is high due to unpredictable differences in frequency, timing and severity of various climatic stresses, each time different combinations of several traits are likely to confer drought resistance. Interaction among traits in determining overall crop response to variable stresses is expected to occasionally enhance the importance of a specific trait in a specific stress situation. In this context it becomes difficult to consider drought resistance as a character with its own identity in terms of inheritance.Assessment and verification of traits based on the use of isogenic lines tends to oversimplify the interactions between traits, as the approach provides information on the effect of a specific trait only in a specific genetic background.At the population level of organisation, the dilemma between selection for individual traits and specific combinations of traits can be translated into the dilemma between selection for individual genotypes and specific combinations of genotypes. The evidence that natural selection under stress conditions has not been able to identify either a single trait or a single genotype with a given adapted architecture of traits, is discussed in relation to germplasm development philosophies to stabilize yield in unpredictably stressed environments. 相似文献
16.
Further increasing yield potential remains one of the main objectives of wheat breeding, even in stressful environments. In
general, past genetic gains were associated with increases in harvest index, and future gains should be related to greater
biomass. Identifying genetic sources for such improvement may be relevant. Researchers of TRITIMED identified DH lines of
durum wheat apparently possessing not only high yield potential but also good yield stability. We aimed to determine physiological
attributes responsible for yield and stability among a set of genotypes derived from two parents (Cham 1 and Lahn) and four
of the most promising lines of the DH population (2401, 2408, 2410, 2517). Seven field trials were carried out within the
Mediterranean agricultural region of the Ebro Valley, under a wide range of conditions (ca 2–10 mg ha−1). In four of these experiments, sub-plots were included with source-sink manipulations imposed after anthesis. Cham 1, a
cultivar known for high yields in semi-arid conditions, showed the highest yield potential. Although it showed less yield
stability than Lahn, even under the lowest yielding conditions its yield was not significantly lower than that of Lahn. RILs
2408, 2410, 2004 and 2517 slightly outyielded Lahn in high-yielding conditions, but under poorer environments they tended
to yield less. Interestingly, yield differences were closely related to their biomass rather than harvest index. Thus yield
differences relating to the number of grains per m2 were due to differences in spike dry matter at anthesis, reflecting in part genotypic differences in crop growth from jointing
to anthesis. In general grain weight did not respond to spike trimming after anthesis, although in two experiments the grain
weight of Cham 1 did so. Thus, even the highest-yielding cultivar possessed grains that overall seemed more limited by its
constitutive capacity to grow than by the availability of resources to reach this capacity (though occasionally they may be
co-limited). Overall, the most interesting feature was the empirical evidence that improvement of biomass within elite material
is a worthwhile objective. 相似文献
17.
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
18.
Progress from plant breeding has been slow in some marginal environments. Conventional or formal plant breeding (FPB) programs
conducted by international agricultural research centres or national programs in developing countries have been criticized
for ignoring indigenous germplasm, failing to breed for conditions facing poor farmers, and emphasizing selection for broad
versus local adaptation. A suite of techniques, referred to as participatory plant breeding (PPB) and including farmer-participatory
or farmer-led selection, on-farm evaluation, and use of local landraces, has been advocated in response to this critique.
PPB programs are diverse in scope and approach, but often rely heavily on farmer visual evaluation or phenotypic mass selection
to select for simply-inherited traits, with limited replicated yield testing in multiple-environment trials (MET), one of
the main tools of FPB. Prediction equations derived from selection theory can be used to examine the conditions under which
idealized versions of FPB and PPB may be expected to achieve genetic progress for traits such as yield. The effectiveness
of any selection environment is determined by both the genetic correlation between genotype performance in it and the target
environment (r
G) and the heritability of genotypic differences in the selection environment (H
s). r is a measure of the accuracy with which performance of genotypes in the selection environment predicts performance in the
target environment; H
s is a measure of the precision with which performance differences among genotypes can be measured in the selection environment.
We compare FPB and PPB with respect to these determinants of selection response, using examples from self-pollinated species.
Particular areas examined include: (i) selection for broad versus specific adaptation; (ii) on-station versus on-farm selection;
and (iii) selection under high-yield versus low-yield conditions. In general, PPB systems attempt to maximize gains through
the use of on-farm evaluation and the skills of farmer-selectors to maximize r
G. FPB exploits METs to maximize H
s. PPB is most likely to develop cultivars that out-perform the products of FPB when it is applied in low-yield cropping systems,
because it is in such situations that r
G between high-yield breeding nurseries and low-yield target environments is likely to be low or negative. To make continued
gains, and to compete with internationally-supported FPB programs, PPB systems will need to counter the obscuring effects
of uncontrollable within-field, site-to-site, and year-to-year heterogeneity. Simple and robust designs for on-farm METs are
needed for this purpose.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
Genotype-by-environment interactions (GEIs) can affect breeding progress because they often complicate the evaluation and
selection of superior genotypes. This drawback can be reduced by gaining insights into GEI processes and genotype adaptation.
Here, we have studied the GEIs over a set of 24 barley genotypes that were grown across six environments (location-by-year
combinations) in Sardinia, Italy. Three groups of genotypes were analysed: barley landraces (LANs), recombinant inbred lines
(RILs), and commercial varieties (VARs). The additive main effects and multiplicative interaction (AMMI) model was used for
data analysis, and results evidenced no significant differences in grain yield averages for the 24 genotypes. However, there
was a relevant GEI for yield mainly between two of the six environments (one characterised by warm pre-anthesis period and
high spring rainfalls, and the other characterised by opposite features) and two groups of genotypes (VAR and LAN). Moreover,
a negative trade-off between yield levels of genotypes was seen when the barley genotypes were grown in the contrasting environments.
Overall, intermediate GEI levels were seen for RILs in comparison to LANs and VARs, and some of the RILs provided valuable
yield levels (e.g. RILs 23 and 52). The results thus show the potential usefulness of LANs as a genetic resource for breeding,
e.g. to obtain genotypes adapted to Mediterranean environments, such as the RILs analysed in this study.
Most of the actual work was carried out when the first author was a PhD student in ‘Agro-meteorology and ecophysiology of
agricultural and forest systems’ and she was affiliated to Dipartimento di Scienze Agronomiche e Genetica Vegetale Agraria,
Università degli Studi di Sassari, Via E. de Nicola, Sassari 07100, Italy. 相似文献
20.
Ram C. Sharma G. Ortiz-Ferrara J. Crossa M. R. Bhatta M. A. Sufian J. Shoran A. K. Joshi R. Chand Gyanendra Singh R. Ortiz 《Euphytica》2007,157(3):457-464
Improving the level and stability of grain yield is the primary objective of wheat breeding programs in the Eastern Gangetic
Plains (EGP) of South Asia. A regional wheat trial, the Eastern Gangetic Plains Yield Trial (EGPYT), was initiated by CIMMYT
in collaboration with national wheat research programs in Bangladesh, Nepal, and India in 1999–2000 to identify wheat genotypes
with high and stable grain yield, disease resistance, and superior agronomic traits for the EGP region. A set of 21 wheat
experimental genotypes selected from a regional wheat screening nursery in South Asia, three improved widely grown cultivars
(Kanchan, PBW343 and Bhrikuti), and one long-term cultivar (Sonalika) were tested at 9–11 sites in six wheat growing seasons
(2000–2005) in the EGP. The 21 experimental genotypes were different in each year, whereas the four check cultivars were common.
In each year, one or more of the experimental genotypes showed high and stable grain yield and acceptable maturity, plant
height, and disease resistance compared to the check cultivars. Three improved cultivars have already been commercially released
in the region through EGPYT and many germplasm lines have been used in the breeding programs as parents. Identification of
wheat genotypes with high-grain yield in individual sites and high and stable yield across the EGP region underlines their
value for regional wheat breeding programs attempting to improve grain yield and agronomic performance. 相似文献