Mungbean is one of the prominent pulse crops in Indonesia since the mungbean seeds are highly nutritious and has become an important part of the diet for the community. The black-seeded mungbean highly nutritious as it contains high anthocyanin content. We have developed a black-seeded mungbean lines that need to be evaluated for drought tolerance. Drought tolerance is important as mungbean is usually cultivated during the drought-prone dry season that leads to total loss. This study aimed to (1) determine the effectiveness of drought tolerance indices to select drought tolerance in black-seeded mungbean, (2) reveal the drought indices most suitable to select drought-tolerant, high- yielding black-seeded mungbean lines. This study was conducted during dry season in the Field Laboratory of Universitas Nusa Cendana. A Split-Plot design was employed, consisting of irrigation frequencies as the main plot and mungbean genotype as the sub- plot treatments. The main plot consisted of three levels, i.e. irrigation every day (I1), every four days (I2), and every seven days (I3), and the subplot consisted of 23 mungbean genotypes. Seed yields under non-stress and stress conditions were used to calculate the drought indices. The data were subjected to ANOVA, PCA and correlation analysis. There were significant variations in seed yields among genotypes under different drought indices. The indices MP, GMP, STI, HARM, MRP, SSI, YSI, MSTIK1, and MSTIK2 are suitable for selection of drought-tolerant, high-yielding mungbean lines. V9.HT, V10.HT, V11.HT, V16.HT, V18.HT, V19.HT, V20.HT, V22.HT were potential for further evaluation as promising drought tolerant, high yielding varieties.
Drought tolerance is derived from complex quantitative traits that are associated with different shoot and root morphological characters. This study assessed the genetic and phenotypic variation of 12 maize inbred lines and performed association analysis of 11 drought-related traits using 360 simple sequence repeats (SSRs), detecting 1,604 alleles, with an average of 4.4 alleles per locus. The average values of gene diversity (GD) and polymorphism information content (PIC) were 0.648 and 0.598, respectively. In principal component analysis (PCA), shoot fresh weight (SFW), shoot dry weight (SDW), stem weight (SW), leaf weight (LW), root fresh weight (RFW), root dry weight (RDW), and leaf area (LA) traits contributed greatly to the PCA. Association analysis was performed using a general linear model with a Q-matrix (Q GLM) and a mixed linear model with Q and K-matrices (Q + K MLM). Twelve SSR markers for drought tolerance trait were detected by Q GLM, and all maize inbred lines were clearly divided into two groups in accordance with their drought tolerance. Duplicated significant marker-trait associations (SMTAs) between Q GLM and Q + K MLM identified eight marker-trait associations involving four SSR markers that were associated with the traits of SW, SFW, RFW, and RDW with a significant level of
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Six durum and twelve bread wheat genotypes were evaluated under favorable and drought-stressed field conditions, and screened with thirty simple sequence repeats (SSR) markers. The traits studied were stomata frequency (STF), relative water content (RWC), flag leaf area (FLA), flag leaf weight (FLW), flag leaf dry matter content (FLD), chlorophyll a content (Chl.a), chlorophyll b content (Chl.b), grain yield/plant (GYP) and 1000-kerenl weight (TKW). Highly significant differences were observed among wheat genotypes for all the traits, indicating considerable genetic variation. Moderate to high broad-sense heritability estimates were observed for the studied traits. Under drought stress, GYP was positively correlated with RWC, FLA, FLW and TKW, whereas negatively correlated with STF. G3 (Svevo) and G6 (WK-12-1) were the most drought-tolerant durum wheat, whereas G11 (L.S-15) and G16 (SIDS-1) were the most drought-tolerant bread wheat genotypes. SSR markers analysis indicated considerable genetic variation between and within durum and bread wheat genotypes. The percentage of polymorphism ranged from 14.3% (Xgwm174-5D) to 100% (Xgwm294-2A and Xgwm573-7B), with an average of 61.4%. The polymorphism information content (PIC) ranged from 0.20 (Xwmc596-7A) to 0.48 (Xgwm294-2A), with an average of 0.33.The highest polymorphism (77.1%) was observed in the B genome followed by A (57.8%) and D (50.0%) genomes. Cluster analysis based on phenotypic data distinguished the most drought-tolerant genotypes (G6 and G11) from the remaining genotypes. Cluster analysis based on SSR markers distinguished durum from bread wheat genotypes. The study indicated that phenotypic data and SSR markers were effective in assessing the genetic diversity in the studied genotypes.
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Drought is one of the most important abiotic factors affecting wheat production and development of tolerant genotypes is limited by the lack of effective selection criteria. A genetic analysis of drought tolerance indices at seedling stage (i.e. root length, shoot length, root/shoot ratio and seedling dry weight) was performed for a seven-parent half diallel cross of bread wheat (
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A set of five Korean rice cultivars and seven drought-tolerant indica lines were screened under irrigated non-stress and drought-stressed conditions in the 2011 and 2012 dry seasons at IRRI, Philippines. The drought-stressed experiment received mild to moderate stress. Under drought stress, ‘IR86918-B-439-B’ had the highest grain yield among all tested lines and ‘Hanarembyeo’ had the highest grain yield among the five Korean rice cultivars. ‘IR86918-B-439-B’ also had the highest yield under irrigated non-stress conditions. The grain yield of ‘Hanareumbyeo’ was similar to ‘IR86918-B-439-B’ under non-stress conditions. SSR marker analysis was performed using 125 SSR markers for detection of polymorphic markers between the Korean rice cultivars and the drought-tolerant indica lines, and for genetic diversity analysis. Twelve polymorphic markers were identified in the region of three major drought QTLs (DTY1.1, DTY2.2, DTY3.1) in two of the Korean rice cultivars and three of the drought-tolerant lines. These polymorphic markers will be useful as foreground genotyping markers for drought-QTL introgression in Korean rice genetic backgrounds.
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Common wheat (
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