GENETIC ANALYSIS OF MORPHO PHYSIOLOGICAL TRAITS RELATED TO WATER STRESS IN RICE (Oryza sativa L.)
Loading...
Files
Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Acharya N.G. Ranga Agricultural University, Guntur
Abstract
The present investigation on “Genetic analysis of morpho physiological traits related to water stress in rice (Oryza sativa L.)” was carried out at Andhra Pradesh Rice Research Institute & Regional Agricultural Research Station, Maruteru during Kharif 2011 & Rabi 2011-2012 and at Rice Research Unit, Bapatla during Kharif -2012 to study the heterosis, combining ability analysis involving ten parents and 24 F1’s, correlation and path analysis and six genetic components in two crosses for nineteen yield and physiological traits under stress and non stress conditions.
Heterosis in F1 hybrids from L x T analysis under water stress condition revealed higher magnitude of heterobeltiosis for number of panicles per plant, grain yield per plant and leaf rolling whereas in case of SPAD chlorophyll meter reading, relative water content, flag leaf area and chlorophyll stability index, it was low. Six cross combinations viz., BPT 5204/Annada, BPT 5204/Rajendra, NLR 34449/Annada, NLR 34449/Ramappa, JGL 3855/Rajendra and IR 64/Annada exhibited high degree of heterosis for grain yield per plant under water stress condition. Such high heterosis for grain yield was due to additive effect of one or more component traits.
The analysis of variance for combining ability for nineteen yield components and physiological traits revealed significant differences among the lines, testers and hybrids evaluated under water stress condition for yield contributing characters and physiological traits. The GCA and SCA variances indicated non additive gene action was predominant
for all the yield components and drought related traits except for days to 50% flowering, yield per plant and chlorophyll stability index where additive gene action was predominant. Based on per se performance, SCA effects and standard heterosis, four cross combinations viz., JGL 3855/Rajendra, MTU 1001/JGL 17004, BPT 5204/Annada, NLR 34449/Ramappa were found promising under water stress condition for most of the yield attributing characters and drought related traits.
Highly significant positive correlations were observed between grain yield and number of panicles per plant, panicle length, filled grains per panicle, harvest index and relative water content under water stress. Path analysis revealed spikelet fertility %, filled grains per panicle and relative water content were the major contributors of grain yield by way of their positive and high direct effect.
The L x T design does not provide comprehensive picture on gene actions governing the traits. Hence, generation mean analysis was done in two crosses viz., MTU 1001/JGL 17004 and NLR 34449/Annada under water stress and non stress conditions to know about epistatic interactions. Significance of one or more of the four individual scaling tests, A,B,C and D revealed presence of epistatic interactions for all the characters in two crosses studied under both non stress and stress conditions except for harvest index in MTU 1001/JGL 17004 under stress condition indicating simple genetic model was inadequate to explain the genetic variation controlling the inheritance of traits.
Estimates of the type of gene action for nineteen traits revealed dominance gene action (h) was the main type of gene effects for both crosses. Additive gene effects are of minor importance in the explanation of traits variation. Though both additive and non additive gene actions were significant, non additive gene actions played predominant role in the inheritance of the traits. Majority of the characters were under the influence of duplicate epistasis for which biparental mating system or reciprocal recurrent selection may be employed to modify the genetic architecture of rice for getting drought tolerance besides high grain yield. The complementary type of epistasis was recorded in MTU 1001/JGL 17004 for plant height, panicle length, and grain yield per plant while in NLR 34449/Annada for number of tillers per plant, filled grains per panicle, and flag leaf area under both situations.
Description
D5182
Keywords
null