Inheritance of traits related to biological nitrogen fixation and genotypic correlation of traits related to nitrogen fixation, yield and drought tolerance in peanut (Arachis hypogaea L.) under early drought.

摘要

The improvement of peanut for drought tolerance and high N₂-fixation is the best way to enhance peanut production under drought condition. Besides, the heritability estimates of traits related N₂-fixation and its genetic correlation with yield and drought tolerant traits are useful to formulate the effective breeding program under drought. Therefore, the aims of this study were to estimate the heritabilities (h2) and genotypic correlation (r_G) among traits related to N₂-fixation (TNf), yield and drought tolerant traits under early drought and non stressed condition. Ninety lines in the F_4:8 generations from four peanut crosses were tested under Field Capacity (FC) and one-third Available Water (1/3 AW). Data were recorded for Nodules Dry Weight (NDW), Biomass Production (BM), Pods Yield (PY), number of pod plant-1, number of seed pod-1 and 100 seed weight at harvest. Specific Leaf Area (SLA), SPAD Chlorophyll Meter Reading (SCMR), Harvest Index (HI) and Drought Tolerance Index (DTI) of PY and BM were measured and calculated as drought tolerant traits. The h2 for BM, PY, number of pod plant-1 and 100 seed weight were high for all tested crosses under both water regimes. With exception of HI trait, high h2 estimates, also, were found for drought tolerant traits under both water regimes. The genotypic correlation (r_G) between NDW and BM was positive highly significant under both 1/3 AW and FC. BM and PY showed high r_G, whereas, BM and 100 seed weight showed moderate r_G. Moderate r_G was found between BM and SCMR 60 DAE under 1/3 AW and FC. Significant correlations between FC and early drought were found for BM indicating that selection of this trait could be done under both water regimes. BM is possible to select and breed for high N₂-fixation, PY and possibly, drought tolerance because of high h2 and significant r_G with PY and SCMR 60DAE.