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991.
Indian gooseberry, one of the most popular medicinal fruit crops in South and Southeast Asia, has become an important source of income for rural forest dwellers in Sri Lanka. However, very little is known about the role of Indian gooseberry in household economies and its contribution to the local and national economies. To address this issue, we conducted a study in Udadumbara Divisional Secretariat, Sri Lanka to estimate the economic contribution of Indian gooseberry to household incomes and to quantify its dependency level among households with different socio-economic characteristics. The data were collected from 117 households through interviews using semi-structured questionnaires. The results show that Indian gooseberry contributes on average 10.1% of the total household income, which is the third largest share after off-farm income (53.1%) and agricultural income (35.1%). The contribution of Indian gooseberry to the household income increases as other sources of income decrease which results in higher contributions for lower income households (16.4%) and lower contributions for higher income households (2.1%). Indian gooseberry income is significantly and negatively correlated with the agricultural land owned by households and water availability for agriculture and is positively correlated with the time spent for collection. Our results also found that if there is access to other sources of income and higher levels of education, the collectors’ dependences on Indian gooseberry are decreased. Moreover, the study found that Indian gooseberry trees are under a threatened and declining due to the reduction of forest cover and inappropriate management system. Therefore, collaborative management system through partnerships among rural community and the Forest Department is suggested.  相似文献   
992.
Agroforestry is one of the most sustainable land management systems practiced around the world due to the socioeconomic benefits that it brings to farmers. In Bangladesh, farmers practice agroforestry, applying indigenous knowledge. The present study was designed to identify the present status, management practices and its role in improving the livelihoods of farmers in northern Bangladesh. Data for the study were collected through quantitative and qualitative methods. A total of 29 tree and 38 agricultural crop species were planted by the102 farmers interviewed. Mangifera indica (relative prevalence 49%) is the most predominant species, followed by Eucalyptus camaldulensis (relative prevalence 35.4%). Farmers of northern Bangladesh plant trees in cropland for fruits (90%), fuel wood (87%) and timber production (79%). Fruit trees were planted with wider spacing while forest and fuel wood species were planted with narrower spacing. Farmer’s livelihoods improved enormously by practicing agroforestry as they have more access to food, fodder and fuel wood which is reflected by greater access to livelihood capitals (except social capital). However, farmers have experienced increased incidences of pests and diseases to the annual crops and trees. Agroforestry practices increases species diversity, ensure economic return and sustain farmer’s livelihoods.  相似文献   
993.
994.
Drought and salt tolerances are complex traits and controlled by multiple genes, environmental factors and their interactions. Drought and salt stresses can result in more than 50% yield loss in Upland cotton (Gossypium hirsutum L.). G. barbadense L. (the source of Pima cotton) carries desirable traits such as tolerance to abiotic and biotic stress along with high fiber quality. However, few studies have been reported on mapping quantitative trait loci (QTL) for abiotic stress tolerance using a permanent bi-parental population in multiple tests. The transfer of drought and salt tolerance from Pima to Upland cotton has been a challenge due to interspecific hybrid breakdown. This issue may be overcome by using introgression lines with genes transferred from Pima to Upland cotton. In this study, four replicated tests were conducted in the greenhouse each for drought and salt tolerance along with another test conducted in a field for drought tolerance using an Upland recombinant inbred line population of TM-1/NM24016 that has a stable introgression from Pima cotton. The objectives of the study were to investigate the genetic basis of drought and salt tolerance and to identify genetic markers associated with the abiotic stress tolerance. A total of 1004 polymorphic DNA marker loci including RGA-AFLP, SSR and GBS-SNP markers were used to construct a genetic map spanning 2221.28 cM. This population together with its two parents was evaluated for morphological, physiological, yield and fiber quality traits. The results showed that drought under greenhouse and field conditions and salt stress in the greenhouse reduced cotton plant growth at the seedling stage, and decreased lint yield and fiber quality traits in the field. A total of 165 QTL for salt and drought tolerance were detected on most of the cotton chromosomes, each explaining 5.98–21.43% of the phenotypic variation. Among these, common QTL for salt and drought tolerance were detected under both the greenhouse and field conditions. This study represents the first study to report consistent abiotic stress tolerance QTL from multiple tests in the greenhouse and the field that will be useful to understand the genetic basis of drought and salt tolerance and to breeding for abiotic stress tolerance using molecular marker-assisted selection in cotton.  相似文献   
995.
Drought is a major abiotic constraint for rice production worldwide. The quantitative trait loci (QTLs) for drought tolerance traits identified in earlier studies have large confidence intervals due to low density linkage maps. Further, these studies largely focused on the above ground traits. Therefore, this study aims to identify QTLs for root and shoot traits at the vegetative growth stage using a genotyping by sequencing (GBS) based saturated SNP linkage map. A recombinant inbred line (RIL) population from a cross between Cocodrie and N-22 was evaluated for eight morphological traits under drought stress. Drought was imposed to plants grown in 75 cm long plastic pots at the vegetative growth stage. Using a saturated SNP linkage map, 14 additive QTLs were identified for root length, shoot length, fresh root mass, fresh shoot mass, number of tillers, dry root mass, dry shoot mass, and root-shoot ratio. Majority of the drought responsive QTLs were located on chromosome 1. The expression of QTLs varied under stress and irrigated condition. Shoot length QTLs qSL1.38 and qSL1.11 were congruent to dry shoot mass QTL qDSM1.38 and dry root mass QTL qDRM1.11, respectively. Analysis of genes present within QTL confidence intervals revealed many potential candidate genes such as laccase, Calvin cycle protein, serine threonine protein kinase, heat shock protein, and WRKY protein. Another important gene, Brevis radix, present in the root length QTL region, was known to modulate root growth through cell proliferation and elongation. The candidate genes and the QTL information will be helpful for marker-assisted pyramiding to improve drought tolerance in rice.  相似文献   
996.
Soybean (Glycine max (L) Merr.) seed is an important source of oil for human consumption. Increasing the percentage of oleic acid in soybean seed oil is an important breeding objective because increasing the oleic acid content improves the oxidative stability of the oil. Extensive literature shows that temperature during seed-fill is positively correlated with the content of oleic acid in soybeans. In addition, it was shown that a maturity QTL was linked to an oleic acid QTL. The Mississippi Delta in the USA is a hot environment where soybean harvest begins in August, which is the hottest part of the season. The purpose of this research was to determine the possibility of developing both early- and late-maturing lines with consistent >?50% oleic acid content in Mississippi. We selected early and late segregants from three genetically different breeding populations also segregating for mid-oleic acid derived from crosses to germplasm N98-4445A, a non-transgenic freely available line with >?50% oleic acid. The selected lines were grown in 2 years in three trials at Stoneville, MS. Results indicated that no late-maturing lines (MG V) met the targeted mid-oleic acid level, whereas MG III and early MG IV lines with oleic acid over 50% were obtained. No maturity-alone effect on oleic acid content was observed, due to the bias of the strong negative correlation between maturity date and mean temperature during seed-fill. This study demonstrated that breeders can effectively develop early soybeans with oleic acid levels greater than 50% for the midsouthern USA.  相似文献   
997.
Selection of oat genotypes combining earliness and short plant height could stimulate oat cultivation worldwide. However, the mechanisms involved with the genetic control of heading date and plant height traits are not fully understood to date. This study aimed to identify genomic regions controlling heading date and plant height in two hulled by naked oat populations and to compare these genomic regions with that of other grass species. Recombinant inbred lines of each population and their parents were genotyped by a 6 K BeadChip Illumina Infinium array and assessed for heading date and plant height in two sowing dates. The quantitative trait loci (QTL) affecting these traits were detected by simple interval mapping. The two oat populations showed different genetic mechanisms controlling heading date. A major QTL was identified in one of the populations, mapped into the ‘Mrg33’ consensus linkage group from the current oat map. Two other QTL were detected into the ‘Mrg02’ and ‘Mrg24’ groups, in the second population. On the other hand, both populations presented the same genomic region controlling plant height. Six SNP markers, mapping on the same linkage group within each population, were associated with the trait, regardless the sowing date, explaining more than 20% of the phenotypic variation. Five of these six markers were mapped into three different linkage groups on the oat consensus map. Genomic regions associated with heading date and plant height in oat seem to be conserved in Oryza sativa L. and Brachypodium distachyon. Our results provide valuable information for marker-assisted selection in oats, allowing selection for earliness and plant height on early segregating generations.  相似文献   
998.
Gossypium barbadense L. cotton has significantly better fiber quality than Upland cotton (G. hirsutum L.); however, yield and environmental adaptation of G. barbadense is not as wide as Upland. Most cotton in the world is planted to Upland cultivars. Many attempts have been made, over a considerable number of years, to introgress fiber quality alleles from G. barbadense into Upland. However, introgression barriers, primarily in the form of interspecific incompatibility, have limited these traditional approaches. The use of chromosome substitution lines (CSL) as a bridge should provide a more efficient way to introgress alleles from G. barbadense into Upland. We crossed 18 G. barbadense CSL to three cultivars and developed a random mated population. After five cycles of random mating followed by one generation of self-pollination to increase the seed supply, we grew the random mated population and used 139 G. barbadense chromosome specific SSR markers to assess a random sample of 96 plants for introgression. We recovered 121 of 139 marker loci among the 96 plants. The distribution of the G. barbadense alleles ranged from 10 to 28 alleles in each plant. Among the 96 plants we found individual plants with marker loci from 6 to 14 chromosomes or chromosome arms. Identity by descent showed little relatedness among plants and no population structure was indicated by a heat map. Using CSL we were able to develop a mostly Upland random mated population with considerable introgression of G. barbadense alleles which should be useful for breeding.  相似文献   
999.
Verticillium wilt (VW, caused by Verticillium dahliae Kleb) is a destructive fungal soil-borne disease in Upland cotton (Gossypium hirsutum L.). High levels of VW resistance can be transferred into Upland from Pima cotton (G. barbadense L.) through interspecific introgression breeding. In this greenhouse study, VW resistance was evaluated in a multi-parent advanced generation inter-cross (MAGIC) introgressed line (IL) population, derived from a random mated Barbadense Upland population with five generations of intermating (called RMBUP-C4) between three Upland cotton cultivars and 18 CS-B Upland lines each carrying a pair of G. barbadense chromosome or arm in the TM-1 background. The objectives of this study were to, (1) evaluate VW resistance of 530 MAGIC ILs in the greenhouse; and (2) to identify lines with VW resistance in the MAGIC population based on a total of three replicated greenhouse tests. Approximately 8 plants for each line in each replicate were grown and screened for VW resistance using three parameters i.e., disease leaf severity rating, percentage defoliated leaves, and percentage infected plants, with a total of ~?25,190 plants evaluated. A correlation analysis indicated that the three parameters were significantly and positively correlated with one another in each test. The disease leaf severity rating was the best parameter to assess VW resistance due to its relatively low coefficient of variation and its higher resolution to differentiate resistant genotypes from susceptible ones. Of the 530 genotypes, 5 showed resistance to VW, namely, NMIL348, NMIL518, NMIL405, NMIL290, NMIL307 and had higher levels of resistance to VW with mean disease leaf severity ratings, percentage of defoliated leaves, and percentage of infected plants across three tests ranging from 0.58–1.46, 9.46–26.74, and 25–95%, respectively. These lines can be used as parental lines to improve VW resistance in cotton breeding programs.  相似文献   
1000.
Faba bean (Vicia faba L.) has high utility as a food and soil fertility improving crop. One of the major fungal pathogens of faba bean is Botrytis fabae, the causative agent of chocolate spot. The disease affects significantly the leaf, stem, pod and seed of faba bean compromise its productivity in the smallholder farming sector. Nonetheless, there are limited resistant/tolerant faba bean varieties available and disease control technology options. Therefore, it was prudent to evaluate faba bean landraces for chocolate spot resistance. Fifty landraces together with ten improved varieties were evaluated both in the field and in the greenhouse under natural and artificial inoculation with previously selected aggressive Botrytis fabae isolate (Iso-016) from West Gojjam, in Ethiopia. There were highly significant differences (p?<?0.001) among the landraces for reaction to the disease and agronomic traits. Significant positive correlation was recorded between reaction of genotypes in the field and greenhouse disease data. The overall mean disease epidemics varied from 92.5 to 697.5 for the area under disease progress curve (AUDPC). The highest level of resistance was found in the ICARDA lines, ILB-4726, ILB-938 and BPL-710. Of all 18 landrace collections displayed significantly lower disease reaction than the susceptible check. However the resistance was moderate. The selected eighteen landraces will be recommended for use in breeding for chocolate resistance. Overall, resistance was highly heritable, suggesting that phenotypic selection can be exploited to improve chocolate spot resistance in faba bean varieties.  相似文献   
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