Genetic Diversity, Population Structure, and Marker-Trait Association for Drought Tolerance in US Rice Germplasm

Abstract

Drought is a major constraint in some rice-growing areas of the United States. Its impact is most severe at the reproductive stage resulting in low grain yield. Therefore, assessment of genetic and phenotypic variation for drought tolerance in US rice germplasm is necessary to accelerate the breeding effort. Evaluation of 205 US rice genotypes for drought tolerance at the reproductive stage revealed tolerant response in rice genotypes Bengal, Jupiter, Cypress, Jazzman, Caffey, and Trenasse. Harvest index and fresh shoot weight were identified as important traits to explain the majority of variability among the genotypes under drought tolerance. Genotyping with 80 SSR markers indicated a low level of genetic diversity in US germplasm. Population structure analysis grouped the genotypes into eight clusters. The genotypes from California, Louisiana, and Arkansas formed distinct subgroups. Texas genotypes were similar to those from Louisiana and Arkansas. Marker-trait association analysis showed significant association of RM570 and RM351 with grain yield, spikelet fertility, and harvest index whereas shoot dry weight showed association with RM302 and RM461. The drought-tolerant genotypes identified in this study and the SSR markers associated with drought tolerance attributes will be helpful for development of improved drought-tolerant rice varieties through marker assisted selection.

Genetic Structure and Geographical Differentiation of Traditional Rice (Oryza sativa L.) from Northern Vietnam

“…The population structure was deduced from a model-based approach using STRUCTURE V 2.3.4 software [ 3 , 6 , 46 , 47 ]. The project was set with a run length of 100,000 burns-in, followed by 100,000 Markov Chain Monte Carlo simulations.…”

“…Genetic differentiation between the two subgroups was estimated by AMOVA based on the NEI distance matrix obtained from POWERMARKER software to justify the suitability of group classification using GenAlEx, version 6.503 [ 3 , 34 , 46 , 47 ] with 999 permutations. The level of genetic differentiation between subgroups was determined using PhiPT in AMOVA, a measure that provides important insights into the evolutionary processes that influence the structure of genetic variation within and among subgroups [ 50 , 51 ].…”

Diallel Analysis of Different Rice Genotypes under Water Deficiency Conditions and Assessing Genetic Diversity Using SSR Markers

“…Utilization of more diverse parents is important to obtain maximum heterosis and the development of transgressive segregates (Verma et al, 2019). The environmental influence on morphological and biochemical markers limits their utility of genetic diversity studies (Bhattarai and Subudhi, 2019). On the contrary, molecular markers are considered a powerful tool for estimation genetic diversity (Smith and Smith, 1992), as they are not influenced by environmental factors.…”

Assessment of Genetic Diversity in Various Yield Traits to Determine a High Yielding New Type of Upland Rice

“…Furthermore, heritability value also determines the selection progress, in which the higher the heritability values, the higher the selection progress will be, and the faster a high-yielding variety will be obtained. Genetic diversity plays an essential aspect in which breeders always work [10], [8], [11], [12].…”