Analysis of combining ability under three levels of nitrogen in diallel crosses of maize (Zea mays L.)

Abstract

Utilization of low nitrogen tolerant maize is the key to sustainable production and food security, and hence present studies were conducted at research farm, Birsa Agricultural University, kanke, Ranchi during rabi 2019-20 to estimate General Combining ability (GCA), and Specific Combining Ability (SCA). Non-reciprocal diallel crossing was performed among eight inbreds. The inbreds and 28 F1 hybrids were evaluated in split plot design where three nitrogen rates (0,100,200 kg/ha) were main plot and 36 genotypes were sub-plot arranged in randomized block design with two replications. Data were analysed using Griffing (1956) method II model II. Analysis of variances for combining ability showed highly significant variation among inbreds and hybrids for alomost all characters and N levels. The GCA effect estimated under all three N levels over two locations suggested that the importance of P1, P6, P7 as the best donors for yield, hundred grain weight and number of cobs per plant. The SCA was highest for yield under all three N levels over two locations in P1 x P2, P1 xP3, P1 xP4, P1 x P5, P3 x P6, P3 x P7, P4 x P7, P5 x P6, P6 x P8 and P2 x P3, P2 x P5, P4 x P5 and P5 x P8 are the products of parents with weak or negative GCA for yield. These crosses are recommended for heterosis breeding.