Assessment of Genetic Heritability in Rice Breeding Lines Based on Morphological Traits and Caryopsis Ultrastructure

Subhas Chandra Roy,Pankaj Shil

doi:10.1038/s41598-020-63976-8

Abstract

Rice (Oryza sativa L) is a most important staple food crop of the world because more than half of the World’s population is dependent on it for their livelihood. Global rice production must be doubled by 2050 to cope up with the situation of population growth. Narrow genetic base in the released varieties has made the improvement in plateaus. Widening the genetic base is necessary to overcome the yield barrier. Hybridization and pre-breeding has been carried out to broaden the genetic base. Heritability and genetic advances were measured in the F5 lines (Tulaipanji × IR64), F3 lines (Tulaipanji × IR64 × PB1460), and F3 lines (Badshabhog × Swarna sub1). Some of the breeding lines were showing promising field performance with high yield potentiality. Wide crosses were performed to widen the genetic base between (Ranjit × O. rufipogon) and (Badshabhog × O. rufipogon) and the heritability pattern of the morphological characteristics in the progeny lines was evaluated. Nutritional quality of the rice grain is totally dependent on the morphology and histological characteristics of the caryopsis which are genetically determined. Caryopses ultrastructural analyses were carried out in seventeen different rice breeding lines through SEM. SEM analysis showed distinguishing ultrastructure in respect to pericarp, testa, aleurone layer, protein bodies and starchy endosperm in the breeding lines with distinctive inheritance pattern. This study provides information about the cross compatibility of the wide hybridization and heritability measures of the morphological traits which may supplement the breeding program to break the yield plateaus.

Highlights

Rice (Oryza sativa L.) is most important and staple food crop because more than half of the world’s population (>3.5 billion) depends on it for their livelihood[1,2,3]
High heritability and genetic advance as a percent of mean was recognized for grain number per panicle (99.77% and 50.98 respectively) and 1000 grain weight (99.29% and 53.19), which showed that the presence of additive gene action for traits expression can be improved by simple selection in the cross Tulaipanji × IR64 (Table 1)
Two promising lines were selected from the cross Tulaipanji × IR64 and one line from triparental cross (Tulaipanji × IR64 × PB1460) with high yield potentiality

Summary

Introduction

Rice (Oryza sativa L.) is most important and staple food crop because more than half of the world’s population (>3.5 billion) depends on it for their livelihood[1,2,3]. Germplasm diversity is considered as the mainstay for crop improvement Breeder can introgress these genetic gain related genes/QTLs using knowledge of molecular breeding techniques such as marker assisted selection[16,17,18,19]. The rice germplasm is a rich reservoir of valuable genes which has accumulated over a period of time and is yet to be exploited fully by plant breeders for varietal improvement[20] Recombined populations such as MAGIC (Multi-parent Advanced Intercross) has been developed to maximize the genotypic diversity in order to increase genetic enhancement[21,22,23]. Morpho-histological (ultrastructure) characteristics of the rice caryopsis have been investigated in situ conditions before and after cooking (retrograded stage) through scanning electron microscope (SEM) to trace the inheritance patterns of these traits in the breeding lines

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Conclusion