Inheritance of grain yield and its components in line by tester method of maize (Zea mays L.)

This study was carried out at the Scientific Agriculture Research Center, Al-Ghab, Syria, during 2013 –2014 growing seasons to estimate heterosis, combining ability, phenotypic correlation and path analysis for plant and ear height, ear length, ear diameter, number of rows per ear, number of kernels per row, 100 kernel weight and grain yield per plant for eighteen hybrids produced by the line × tester method, the major findings were: inbred lines, testers, hybrids and combining ability mean squares were significant for all traits, indicating that additive and non-additive gene actions were the important in inheritance of all traits. The ratios of σ2 GCA/σ2 SCA showed that non-additive gene action was more important in controlling all traits except of number of kernel per row. Heterosis percentage for all traits were significant compared with the check variety except of ear height trait. GCA effects showed that the lines P1 and P7 were good combiners for grain yield per plant, also, SCA effects showed that P2×P8, P5×P8, P4×P9 and P1×P7 crosses were the best F1 combiners for grain yield per plant. Results of phenotypic correlation and path analysis values showed that ear length, ear diameter and number of kernel per row were positively and significantly associated with grain yield per plant, also, these traits can be considered as selection criteria may lead to the improvement of grain yield in maize.

The phenotypic correlation and path analysis coefficient for grain yield and its components in four local maize (Zea mays L.) genotypes

The present investigation was undertaken to estimate phenotypic correlation and path coefficient analysis for grain yield and its components in maize. Four local genotypes of yellow maize were evaluated in 2008 and 2009 growing seasons at two locations i.e. Damascus and Dir Al-Zor under three nitrogen fertilization levels (130, 195 and 260 of N. ha-1), The nitrogen fertilizer was applied at two splits. Split split plot design was used with 4 replications. Results of phenotypic correlation values showed that grain yield at Damascus location was positively and significantly associated with ear height (r= 0.204**), ear length (r= 0.205**) and number of rows per ear (r= 0.228**). On the other hand, grain yield at Dir Al-Zor location was positively and significantly associated with all studied traits at combined data whereas, it was positively and significantly associated with ear length at three levels and combined data (0.305*, 0.410**, 0.347** and 0.375**, respectively). The data of path coefficient analysis showed that ear length, ear height and number of rows per ear had positive direct effects on grain yield variation and thus grain yield improvement can be achieved through selection for ear length and ear height at Damascus location (11.06%). On the other side, data showed that each of ear height, number of kernels per row and 100-kernel weight had positive direct effects on grain yield variation (32.98%) and thus, 100-kernel weight can be considered as selection criteria may lead to the improvement of grain yield in yellow maize at Dir Al-Zor location.

The phenotypic correlation and path analysis coefficient for grain yield and its components in four local maize (Zea mays L.) genotypes

The present investigation was undertaken to estimate phenotypic correlation and path coefficient analysis for grain yield and its components in maize. Four local genotypes of yellow maize were evaluated in 2008 and 2009 growing seasons at two locations i.e. Damascus and Dir Al-Zor under three nitrogen fertilization levels (130, 195 and 260 of N. ha-1), The nitrogen fertilizer was applied at two splits. Split split plot design was used with 4 replications. Results of phenotypic correlation values showed that grain yield at Damascus location was positively and significantly associated with ear height (r= 0.204**), ear length (r= 0.205**) and number of rows per ear (r= 0.228**). On the other hand, grain yield at Dir Al-Zor location was positively and significantly associated with all studied traits at combined data whereas, it was positively and significantly associated with ear length at three levels and combined data (0.305*, 0.410**, 0.347** and 0.375**, respectively). The data of path coefficient analysis showed that ear length, ear height and number of rows per ear had positive direct effects on grain yield variation and thus grain yield improvement can be achieved through selection for ear length and ear height at Damascus location (11.06%). On the other side, data showed that each of ear height, number of kernels per row and 100-kernel weight had positive direct effects on grain yield variation (32.98%) and thus, 100-kernel weight can be considered as selection criteria may lead to the improvement of grain yield in yellow maize at Dir Al-Zor location.