Direct Selection for Grain Yield under Moisture Stress in Oryza sativa cv. IR58025B × Oryza meridionalis Population

Abstract

Rice {Oryza sativa L.) is one of the important food crops drastically affected by drought. Considering the low heritability of grain yield under water stress, several secondary traits associated with drought tolerance have been used, but the success achieved in deriving cultivars with high yield potential under stress is less compared to irrigated conditions. Hence, objective of the experiment was to estimate heritability for grain yield under lowland stress and select for grain yield per se using wild species Oryza meridionalis Ng and also to identify physio-morphological traits responsible for withstanding water stress. A population derived from O. sativa cv. IR58025B X O. meridionalis (BC^Fg) was evaluated under control and stress conditions. Variability observed for yield and component traits indicated 0. meridionalis to be a good source of useful alíeles for drought tolerance. Broad-sense heritability {h^) of grain yield under stress, although only 33.1%, was comparable to control 59.4%, indicating direct selection for grain yield per se can be practiced. Twenty high-yielding selected lines and 40 random lines were evaluated under control and stress conditions to estimate selection response. Yield of selected lines outperformed random lines and checks under stress. Furthermore, 10 lines (5 high yielding and 5 low yielding) selected from the population were characterized for root morphological traits. Maximum root length (MRL) and root volume (RV) of selected high-yielding lines recorded maximum compared with checks and low-yielding lines indicating positive influence of drought avoidance root traits on grain yield under stress. Hence, O. meridionalis can be a good source of root traits contributing to stress tolerance and selection for grain yield under stress is an effective strategy in deriving drought tolerant lines in rice.

Genetic gain for rice yield in rainfed environments in India

“…For long-term genetic improvement of yield, evaluating the genetic variation present in the germplasm is a pre-requisite ( Allard, 1960 ; Falconer and Mackay, 2004 ), as availability of adequate variability provides a range of choices from which selections can be made. Genetic variability for yield under drought stress in rainfed lowland rice in both dry and wet seasons have been documented ( Venuprasad et al, 2007 ; Kumar et al, 2007 ; Verulkar et al, 2010 ; Gouda et al, 2012 ; Saikumar et al, 2016 ; Shaibu et al, 2017 ). The genotypic variance component observed for yield under irrigated control and two stress levels in the present study was larger than that of the genotype × year and the genotype × site variance components suggesting enough genetic variability in the breeding material used.…”

Identification of Drought Tolerance Markers in a Diverse Population of Rice Cultivars by Expression and Metabolite Profiling

“…Traditionally, breeding of drought-tolerant cultivars relied on selection based on phenotypic and physiological traits observed under drought stress [8], [9], namely leaf rolling [10]–[12], cell membrane stability [13], carbon isotope discrimination, gas exchange and chlorophyll fluorescence measurements [14]–[19], stomatal conductance and water use efficiency [19], [20], root traits [21] and yield [22], [23]. However, this selection process is labour-intensive and slow as it requires cultivation of breeding populations under drought conditions [24].…”

Food, Nutrition and Agrobiodiversity Under Global Climate Change

“…Grain yield under drought is a complex trait, and grain yield heritability in drought-prone environments is relatively low compared to irrigated control (Venuprasad et al, 2007). Gouda et al (2012) evaluated O. sativa IR58025B × Oryza meridionalis BC 2 F 3 derivatives under water stress to estimate heritability for grain yield and identify physiomorphological traits associated with enhanced adaptation to drought. The broad-sense heritability for grain yield under water stress was 33% compared to 59% under irrigated control.…”