Relationship between combining ability of grain yield and yield components for some newly yellow maize inbred lines via line x tester analysis

الملخص EN

This study was conducted to estimate general and specific combining ability effects of eleven parental lines and their crosses with two single crosses for grain yield (GY) and some of the yield components traits (YCTs) and to study the relationship between grain yield combining ability and the yield components traits (YCTs) combining ability by line x tester analysis.

Therefore, eleven new yellow maize inbred lines were topcrossed with two yellow crosses as testers at Ismailia Agri.

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during 2011 growing season.

In 2012 season, the 22 crosses were evaluated in a replicate trail at two locations; Ismailia and Mallawy Agric.

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Data were recorded on number of days to 50% silking (SD), plant height (PHT, cm), ear height (EHT, cm), number of ears 100 plants-1 (E100P), grain yield ard fed-1 (GY), grain yield plant-1 (YP g), ear length (EL, cm), ear diameter (ED, cm), number of rows ear-1 (RE) and number of kernels row-1 (KR).

Significant differences were observed between the two locations for all of the studied traits, indicating that environmental conditions were different to both locations.

Mean squares due to crosses and their partitioning into lines, testers and line x tester were significant for all of the studied traits except SD for lines; EHT and EL for testers and E100P for lines x tester interaction.

Inbred line 5087 had negative and significant GCA effects for SD, PHT, and EHT toward earliness, shorter plants and lower ear placement.

While, inbred lines; L5303, L5415, L5522 and L5844 had positive and significant GCA effects for grain yield (ard fed-1) and grain yield plant-1 (g).

Results showed that GCA effects of grain yield (GY) were related to GCA effects of the yield component traits (YCTs) in an inbred line.

Significant positive GCA effects for grain yield (GY) were highly correlated with that had significant positive GCA effects, indicating that line with high GCA effects for grain yield (GY), generally had high GCA effects for the yield component traits (YCTs) with high GCA effects.

Thus, selecting inbred lines with positive GCA effects in either all or most of the yield component traits (YCTs) will have greater chance to produce crosses with higher grain yield.

The non-additive gene action played an important role in the inheritance of SD, PHT, EHT, EL, ED, RE and KR.

While, the additive type of gene action played an important role in the inheritance of E100P, GY and YP.

Non-additive gene action was affected more by environmental conditions than additive type of gene action.

Three top crosses; L5522 x SC168 (36.81), L5844 x SC168 (36.92) and L5415 x SC168 (38.09 ard fed-1) were significantly superior compared with the higher check hybrid TWC353 (33.51 ard fed-1 ± 3.22) for grain yield.

Meanwhile, the same three top crosses were significantly superior for grain yield plants-1 (g) compared with higher check hybrid TWC353 (193.25 g ± 17.69).

In addition, two top crosses; L5303 x SC168 (33.74) and L5323 x SC168 (33.91 ard fed-1) were not significantly different from the high yielding check hybrid.

These top crosses have to be evaluated in the advanced stage for release as new commercial hybrids in maize research program