Genetics of SPAD Chlorophyll Meter Readings and Kernel Yield in Maize (Zea mays L.)

Abstract

The present study evaluated 45 single cross hybrids generated by involving ten inbred lines in RBD across three seasons for yield and yield attributing traits, combining ability and heterosis. Kernel yield is a complex trait influenced by several yield contributing traits. Chlorophyll is a vital pigment for absorbing, transferring and transforming in photosynthesis. Chlorophyll meter readings have been used in many annual crops to estimate nitrogen status. Hybrids with higher SCMR readings were consistent across seasons emphasizing the stability of the character. Hence, selection for SPAD meter reading could potentially be an effective physiological trait in breeding programmes. Additive and non-additive gene actions were involved in controlling SCMR and kernel yield with a greater role of non-additive gene actions. Standard heterosis varied from 11.22 to 25.11 and from -2.74 to 6.00 and sca effects ranged from -1.67 to 4.98 and from -0.9 to 2.67 for kernel yield and SCMR, respectively in the top yielding hybrids. Among the top 10 hybrids, BML 15 x PDM 1474 and BML 7 x DFTY (poor x good) and BML 15 x PDSM 1452 (poor x poor) with high per se performance for kernel yield and SCMR, significant sca and standard heterosis may be utilised for exploitation of hybrid vigour or development of hybrids. The hybrids Heypool x PDM 1474 and DFTY x Heypool (good x good) with high mean performance for kernel yield and SCMR, significant standard heterosis and non-significant sca effects may be handled through pedigree breeding so as to capitalize additive × additive gene action or may be utilized in the improvement of inbreds or parental lines through recycling. The two hybrids viz; DFTY × PDM 1452 (good x poor) and BML 6 × PDM 1474 (poor x good) with high mean for kernel yield and SCMR, significant sca effects and standard heterosis may be handled though population improvement programmes so as to isolate superior parental lines or to obtain superior hybrids through recurrent selection.