HAPLOTYPE ANALYSIS OF MOLECULAR MARKERS LINKED TO EARLY SEEDLING VIGOUR RELATED TRAITS IN A SET OF RICE (Oryza sativa L.) GENOTYPES
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Date
2024-04-24
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Acharya N G Ranga Agricultural University
Abstract
Rice is the most important and staple food crop in the world. The eventual
shifting of cultivation from puddle transplanted rice (PTR) to direct seeded rice
(DSR) to save water prompted breeders to identify the donor parents, genes,
haplotypes and cross combinations suitable to develop varieties for dry DSR
conditions. The present investigation was carried out on haplotype analysis of
molecular markers linked to early seedling vigour-related traits using 40 rice
genotypes.
From the mean performance, the genotypes SM211, BMF536, BMF517,
BMF574 and 81C were found superior with higher grain yield plant-1. The
genotypes, Lalanakanda, Varalu, BMF536, BMF517 and MM129 registered
desirable performance under dry DSR conditions for most of the characters
studied.
The characters, number of chaffy grains panicle-1, 1000-grain weight,
grain yield plant-1, number of filled grains panicle-1 and seedling vigour index –
II recorded high PCV, GCV, heritability (broad sense) and genetic advance as
per cent of mean indicating these characters are amenable for simple phenotypic
selection for further improvement.
Mahalanobis’s D2
analysis grouped 40 genotypes into eight clusters based
on yield, yield attributes and early seedling vigour-related traits. A perusal of the
results revealed Cluster I to be the largest comprising of 23 genotypes followed
by cluster II comprising of 7 genotypes and Cluster III with 5 genotypes.
Whereas, clusters IV, V, VI, VII and VIII had single genotype. Among all the
traits studied, seedling vigour index-I followed by seedling vigour index-II and
days to maturity contributed relatively maximum towards total genetic
divergence. Molecular diversity analysis with markers related to early seedling
xv
vigour traits using DARwin software grouped the 40 rice genotypes into 3
clusters.
From character association studies, grain yield plant-1 was found to
possess significant positive association with traits viz., days to 50% flowering,
days to maturity, plant height, panicle length, number of panicles plant-1, number
of filled grains panicle-1, number of chaffy grains panicle-1, 1000 grain weight,
grain breadth and seedling height whereas spikelet fertility exhibited negative
significant association with grain yield plant-1
.
Haplotype analysis of molecular markers linked to early seedling vigour related traits was carried out using flanking markers of three QTLs viz., qSV-6a
(RM204 and RM402) for root length; qVI (RM20429 and RM3) for seedling
vigour index; qGP-6 (RM528 and RM400) for germination percentage on
chromosome 6. Haplotype analysis of these molecular markers grouped the 40
rice genotypes into different haplotypes which were significantly different
according to students’s t-test and this helped in the identification of rice
genotypes with superior and novel haplotypes. These could be utilized to develop
rice varieties suitable for dry DSR conditions.