Seed and seedling vigour traits in groundnut (Arachis hypogaea L.)

Experiments were conducted with groundnut (Arachis hypogaea L.) germplasm accessions and cultivars to identify agronomic desirable traits associated with seed and seedling vigour. Seed vigour was assessed under optimum conditions in dormant (ICGS 11) and non-dormant (GG 2) seeded cultivars. Wide genetic variations were recorded in the parameters such as germination rate, germination speed, co-efficient of germination, vigour index, respiration rate and number of secondary roots. Genetic variations were observed in germinability, and root, hypocotyl and epicotyl lengths, opening of cotyledons, and growth of secondary roots in germplasm accessions and cultivars evaluated for tolerance to drought and high temperature stresses, under simulated conditions. Promising cultivars viz. TAG 24, Girnar 1, J 11 and KRG 1. all belonging to the Spanish market type, suitable for sowing in drought prone areas were identified. Germplasm accessions viz. NRCG 12752 (SHANTUNG) and 12642 (57-C-3-4-4-1-1-1) tolerant to high temperature during germination in(] early seedling growth were also identified. Utilisation of reserve food material, evaluated in 10 cultivars, belonging to three different seed-weight groups and Virginia and Spanish market types, indicated that both medium and higher seed-weight groups are efficient in utilisation of reserve food material. The lower seed-weight group was found inefficient in supply of reserve food material stored in the cotyledons to establish vigorous seedlings. A significant inverse relationship (r = -0.71, n = 15) between specific leaf area (SLA) and total seedling biomass was established, i.e., the lower the SLA (thicker leaf) the higher the biomass. and the higher the SLA (thinner leaf) the lower the biomass. Thus the parameters such as 100-seed weight, efficient utilisation of reserve food material, development of secondary roots and lower SLA are desirable agronomic traits in groundnut cultivation, especially in rain-dependent systems. In addition, the tolerant lines/cultivars Could be utilised as donor parents in improving groundnut cultivars for higher seed vigour through breeding.