Molecular, anatomical and physiological diversity for water use efficiency traits in rice (Oryza sativa L.)

Abstract

This study was conducted to evaluate the genetic diversity of 48 rice genotypes for water use efficiency related traits in relation with molecular diversity to identify water stress tolerant genotypes. The results indicated that water stress tolerant varieties had lower number of stomata with increase in the size of guard cells and increased distance between stomata, lesser carbon isotope discrimination, and higher leaf relative water content and with less specific area than water stress susceptible varieties. Significant negative relationship between carbon isotope discrimination and stomata size and distance between stomata reveals that lesser 13C discrimination. Significant negative relationship between relative water content and stomata number on leaf surface indicates maintenance of water status under stress conditions. There is no significant relationship between specific leaf area and relative water content, specific leaf area and stomata characters. Molecular diversity using SSR markers provided the dendrogram with four clusters showing the differentiation in genotypes for water stress tolerance. This implies the use of member of these clusters as parents to build up population for selection of transgressive segregants against water stress in subsequent generations and for the development of QTLs related with water stress tolerance.