Abstract
A panel of 60 genotypes comprising New Plant Types (NPTs) along with indica, tropical and temperate japonica genotypes was phenotypically evaluated for four seasons in irrigated situation for grain yield per se and component traits. Twenty NPT genotypes were found promising with an average grain yield varying from 5.45 to 8.8 t/ha. A total of 85 SSR markers were used in the study to identify QTLs associated with grain yield per se and related traits. Sixty-six (77.65%) markers were found to be polymorphic. The PIC values varied from 0.516 to 0.92 with an average of 0.704. A moderate level of genetic diversity (0.39) was detected among genotypes. Variation to the tune of 8% within genotypes, 68% among the genotypes within the population and 24% among the populations were observed (AMOVA). This information may help in identification of potential parents for development of transgressive segregants with very high yield. The association analysis using GLM and MLM models led to the identification of 30 and 10 SSR markers associated with 70 and 16 QTLs, respectively. Thirty novel QTLs linked with 16 SSRs were identified to be associated with eleven traits, namely tiller number (qTL-6.1, qTL-11.1, qTL-4.1), panicle length (qPL-1.1, qPL-5.1, qPL-7.1, qPL-8.1), flag leaf length (qFLL-8.1, qFLL-9.1), flag leaf width (qFLW-6.2, qFLW-5.1, qFLW-8.1, qFLW-7.1), total no. of grains (qTG-2.2, qTG-a7.1), thousand-grain weight (qTGW-a1.1, qTGW-a9.2, qTGW-5.1, qTGW-8.1), fertile grains (qFG-7.1), seed length-breadth ratio (qSlb-3.1), plant height (qPHT-6.1, qPHT-9.1), days to 50% flowering (qFD-1.1) and grain yield per se (qYLD-5.1, qYLD-6.1a, qYLD-11.1).Some of the SSRs were co-localized with more than two traits. The highest co-localization was identified with RM5709 linked to nine traits, followed by RM297 with five traits. Similarly, RM5575, RM204, RM168, RM112, RM26499 and RM22899 were also recorded to be co-localized with more than one trait and could be rated as important for marker-assisted backcross breeding programs, for pyramiding of these QTLs for important yield traits, to produce new-generation rice for prospective increment in yield potentiality and breaking yield ceiling.
Highlights
Rice (Oryza sativa L.) is a staple food crop sustaining more than 3.5 billion people in the globe
This study primarily focused on 11 yield and yieldrelated traits, namely, days to 50% flowering (DFF), plant height (PH), tiller number (TL), panicle length (PL), flag leaf length (FLL), flag leaf width (FLW), no of fertile grains (FG), total no of spikelets per panicle (TG), 1000-grain weight (TGW), seed length-breadth ratio (SLBR) and grain yield t/ha (YLD)
The analysis indicated that the traits viz., thousand grain weight (TGW), SLBR, TL, FLL, FLW, PL and YLD were predominant for the genotypes situated in the green circle in quadrant I (S5 Table)
Summary
Rice (Oryza sativa L.) is a staple food crop sustaining more than 3.5 billion people in the globe. A breakthrough in productivity barrier is necessitated because of increasing competition for natural resources such as, land, water and others given population explosion coupled with expanding industrialization, urbanization and diversion of agricultural land [1,4,5]. This is further aggravated with the abnormal change in weather and climate with significant influence on crop productivity and quality [6,7]
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