BREEDING FOR DEVELOPMENT OF WHITE HYBRID MAIZE (Zea mays L.)

Abstract

The study consisted of four experiments which were conducted to characterize fifty eight inbred lines, determine the genetic variation, explore the genetic diversity, select the suitable parents their combining ability and heterosis as well as evaluate genotypeenvironment

interaction in order to identify potential white maize hybrids during the period from November 2015 to July 2018 at Regional Agricultural Research Station (RARS), Rahmatpur, Barishal along with other four regional stations of Bangladesh Agricultural Research Institute (BARI) i.e Jashore, Jamalpur, Chattogram and Dinajpur. Eleven qualitative and ten quantitative characters were studied during morphological characterization. Based on statistical analysis of the morphological traits of the inbred lines, wide variability was found for all the characters studied and thus offered scope for selection of parental lines. Plant height, number of kernel per row, thousand grain weight and grain yield, were governed by additive genes effect, as demonstrated by high heritability and high genetic advance in percentage of mean. Days to tasseling, days to silking, ear height, ear length, ear diameter, number of kernels per row, 1000 grain weight showed significant positive correlation with grain yield both at phenotypic and genotypic levels indicating dependence of these characters on grain yield. Path coefficient analysis revealed that among the characters except silking date and plant height other characters viz., Days to tasseling, ear diameter, number of kernel per row, ear height, thousand grain weight, ear length and number of row per ear had positive direct effect on grain yield. The diversity analysis showed that the fifty-eight inbreds were clustered into seven diverged groups. On the basis of the findings of the present study the inbred lines from cluster I, IV and VII were selected as better parents (CML 330, CML 332, CML 322, CML 311, CML 331, CML 518, CML 383). The estimate of GCA effects showed that the parents P6 (CML 518), P7 (CML 383), P3 (CML 322) and P4 (CML 311) were good general combiners for improving the yield and yield contributing traits. Among all the crosses, the cross combinations CML 311×CML 331(E16), CML 331×CML 383(E20) and CML 332×CML 518(E10) were the best specific combiners for yield. The result of standard heterosis comparison with BHM 12 and BHM 13 showed that out of twenty one hybrids, only four hybrids i.e CML 322×CML 518(E14), CML 311×CML 331(E16), CML 331×CML 383(E20) and CML 332×CML 518(E10) manifested significant positive heterosis. In genetic and environmental interaction analysis the AMMI biplot analysis indicated E24 (BARI Hybrid Maize 14), E16 (CML 311×CML 331), E13 (CML 322×CML 331), E17 (CML 311×CML 518) and E14 (CML 322×CML 518) were positioned closer to the origin of the biplot which indicated their stability in performance across environments. When genotypes were compared with ideal genotypes which has both high mean yield performance and high stability across environments it was observed that E14 (CML 322×CML 518), E16 (CML 311×CML 331), E10 (CML 332×CML 518) and E20 (CML 331×CML 383) were nearest to the ideal genotypes. Considering overall performance on yield, yield contributing characters, combining ability and stability, E14 (CML 322×CML 518) and E16 (CML 311×CML 331) cross combination were found superior.