Divergence studies in elite salt tolerant lines under direct seeded condition in rice (Oryza sativa L.)

Abstract

Salinity is a major constraint in coastal agriculture due to seawater intrusion, tidal flooding and poor drainage. Hence it is imperative and viable option to grow salt tolerant lines with high yield potential and amenable for direct seeded conditions in flood prone coastal belts. In the present study 24 elite salt tolerant lines developed at ARS Machilipatnam (EC 9-10 dSm^-1, pH 7.9) under transplanted conditions were evaluated under direct seeded conditions along with two checks during kharif, 2023 at Agricultural College Farm, Bapatla, Andhra Pradesh in a randomized complete block design (RCBD) with two replications, in a normal soil condition (EC 2.5 dSm^-1, pH 7.2). Observations on yield and yield components; early vigour and lodging related traits were studied under direct seeded conditions. The results revealed that first six principal components accounted for 89.59 per cent of total divergence. PC₁ contributed maximum towards divergence (30.64 %) with eigen value of 6.435. Based on the analysis and loading values PC₅ contributed to most of direct seeded and yield traits viz., root volume at 15 DAS, days to 50 per cent flowering, plant height, grain yield and harvest index in PC₅ followed by shoot length at 30 DAS, field emergence at 15 DAS, root volume at 30 DAS, spikelet fertility in PC₃ and root length at 15 DAS, panicle length, basal internodal length and culm thickness in PC₂. The 2D and 3D plots indicated that genotypes like MCM 148-2-1-1-1, MCM 141, MCM 153-2-1-2-1, MCM 103, MCM 153-1-1-1, MCM 305-32-2-1 and MCM 151-3-21-1 were divergent for most of the direct-seeded traits like root length, shoot length, root volume, basal internodal length and culm volume. Among the 14 SSR markers studied, RM5, RM10793, RM3412 and RM1287 recorded higher PIC values. Hence, these markers can be considered more informative and are capable of discriminating the genotypes more effectively.