Genetic variability for iron and zinc as well as antinutrients affecting bioavailability in black gram (Vigna mungo (L.) Hepper)

The mineral content of pulses is generally high, but the bioavailability is poor due to the presence of phytate and polyphenols which inhibits Fe absorption. In the present study, the genetic variability and heritability for seed Fe and Zn content was studied. The effect of genotypes was significant for all the quality traits indicating presence of enough variability among the blackgram genotypes for the traits. The Fe content in 26 blackgram genotypes ranged from 71.02 to 100.20 ppm, whereas Zn content ranged from 18.93 to 60.58 ppm. Maximum Fe as well as Zn was recorded in genotype SHEKHAR 2 (100.2 and 60.58 ppm respectively). The Phytic acid and polyphenol content among genotypes varied significantly and it ranged from 0.06-0.37% to 5.88-9.03 mg/g, respectively. High phytic acid content was recorded in black gram genotypes COBG 653, Nodai Urd, NP 03 and PKG U 03, whereas high polyphenol content was recorded in PU 31, IPU 99-200, PDU 1 and YAKUBPUR 2. Blackgram genotype COBG 653 had high phytic acid but low polyphenol content. The genotype × year interaction was significant for all the traits under study which indicates differential reaction to the expression of quality characters over years. Fe content in blackgram genotypes showed significant positive phenotypic correlation with Zn content while at genotypic level in addition to Zn, it showed positive correlation with phytic acid and polyphenol content as well. This indicates that although the traits are genotypically correlated, the expression is masked by the environmental influence. This is further exhibited from low heritability estimates for phytic acid and polyphenol content among the genotypes.