MARKER ASSISTED INTROGRESSION OF DROUGHT TOLERANCE AND PHOSPHORUS UPTAKE QUANTITATIVE TRAIT LOCI INTO RICE (Oryza sativa L.)
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Date
2021-12-06
Authors
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Publisher
Acharya N.G. Ranga Agricultural University, Guntur
Abstract
The present investigation was carried out with breeding material consisting 24
BILs of qDTY3.1 positive lines and 26 BILs of Pup1 positive lines along with two
recurrent parents IR58025B and KMR-3R and two QTL donors viz., Apo for qDTY3.1
QTL and Kasalath for Pup1 QTL respectively.
The genetic materials of different generations viz., F1, BC1F1, BC2F1 and BC2F2
of two crosses IR58025B x Apo and KMR-3R x Kasalath were developed during kharif
2016 to rabi 2018 by using introgressive backcrossing of marker selected QTL
genotypes with recurrent parents involving precise foreground and background
selection strategy. RM 520 SSR marker was used for the foreground selection of the
qDTY3.1 in F1, BC1F1, BC2F1 and BC2F2 generations of IR58025B x Apo while
background selection was performed for the same set of BILs with 88 polymorphic SSR
markers. Foreground selection of Pup1 QTL was done with two SSR markers viz.,
K-46-1 and K-46-2 in F1, BC1F1, BC2F1 and BC2F2 generations of KMR-3R x Kasalath.
Inaddition, 86 polymorphic SSR markers were used for background selection in BILs of
KMR-3R x Kasalath.
The BILs identified from BC2F2 generation of each cross were evaluated in two
separate experiments during rabi 2018 at IIRR, Rajendranagar, Hyderabad in a
completely randomised block design with two replications under both control
(non-stress) and stress condition.
The experiment-I consisted of 24 BILs of qDTY3.1 positive lines derived from
BC2F2 generation of cross IR58025B x Apo and were evaluated at IIRR, Rajendranagar,
Hyderabad during rabi 2018 under both control and reproductive stage moisture stress
conditions in order to identify backcross inbred lines with higher grain yield under
reproductive stage moisture stress.
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Analysis of variance revealed the existence of significant differences among the
BILs in both reproductive stage moisture stress and control conditions for all traits
except for panicle length.
Correlation analysis revealed highly significant positive association of grain
yield per plant with harvest index, filled grains per panicle, spikelet fertility and
biological yield per plant under both control and moisture stress whereas plant height,
number of tillers per plant, number of panicles per plant, 1000 grain weight, shoot
length and SCMR showed significant positive association under reproductive stage
moisture stress. Seven BC2F2 introgressive lines viz., GSD-2, GSD-4, GSD-12,
GSD-16, GSD-20, GSD-21 and GSD-23 were selected as qDTY3.1 positive lines with
higher yield under both control and reproductive stage moisture stress conditions
respectively and could be promising donors for improvement of rice cultivars for
reproductive stage moisture stress condition.
The experiment-II comprised of twenty six Pup1 positive back cross inbred lines
(BC2F2) derived from crossing of KMR-3R with Kasalath and were evaluated at IIRR,
Rajendranagar, Hyderabad during rabi, 2018 on experimental fields at normal P
(> 18.3 ppm) and low P (< 2 ppm) conditions so as to identify the backcross inbred
lines with higher grain yield under low P deficient conditions.
Analysis of variance indicated the existence of significant differences among the
BILs in both low P and normal P environments for all traits except for number of tillers
per plant, number of panicles per plant and unfilled grains per panicle.
A perusal of character association indicated highly significant positive
association of grain yield per plant with harvest index, spikelet fertility and leaf P in
both conditions. Number of tillers per plant, number of panicles per plant, filled grains
per panicle and leaf P displayed significant positive association with grain yield per
plant under low P conditions. Seven BC2F2 introgressive lines viz., GSP-2, GSP-4,
GSP-12, GSP-16, GSP-20, GSP-23 and GSP-26 were confirmed as Pup1 QTL positive
lines with higher grain yield under both low P and normal P conditions and could be
utilized in breeding programme for development of cultivars of rice for low āPā
condition.
Description
MARKER ASSISTED INTROGRESSION OF
DROUGHT TOLERANCE AND PHOSPHORUS
UPTAKE QUANTITATIVE TRAIT LOCI INTO
RICE (Oryza sativa L.)