Hardness Breaking Force: an Alternative Method to Evaluate Hardseededness in Mung Bean (vigna Radiata)

The presence of hard seeds in seed lots reduces field emergence percentage leading to poor and non-uniform plant establishment, and uneven maturity. The routine procedure for evaluation of hardseededness is a standard germination test that requires seven days. An alternative rapid procedure for large-scale screening of breeding materials for hardseededness is needed. Fifty-one mung bean genotypes were grown in two years with similar growing conditions (Kharif 2016 and Kharif 2017) and the number of hard seeds was recorded at the end of a standard seed germination test. The hardness breaking force (Newtons) was measured using a texture analyser machine for three replicates of ten seeds for each genotype and harvest year. The genotypes were classified into three groups: seeds that required a low (< 27 Newtons), medium (28-56N) and high (> 56N) hardness breaking force. Seven genotypes required an average hardness breaking force of 22.2 and 22.32N for seeds from Kharif 2016 and 2017, respectively, with mean percentages of hard seeds of 7.83 and 8.25%. Similarly, 26 genotypes from both Kharif 2016 and Kharif 2017 required a hardness breaking force of 40.72 and 41.21N, with average percent hard seeds of 18.1 and 18.7%, respectively. Eight genotypes from both years required a mean hardness breaking force of 62.9 and 63.75N with average percent hard seeds of 27.2 and 27.25%, respectively. The hardness breaking force character was stable over the two years. Thus, this parameter can be used as an alternative to a standard germination test for rapid screening for hardseededness.