Combining ability of newly developed white maize (Zea mays L.)‎ inbred lines via top cross analysis

الملخص EN

Twelve newly developed white maize inbred lines were crossed with two testers i.

e.

SC 128 and SC 131 at Ismailia Agricultural Research Station during 2017 season.

In 2018 summer season, the 24 top crosses and two white commercial check hybrids; TWC 321 and TWC 324 were evaluated under two locations (Loc); Ismailia and Mallawy Agricultural Research Stations.

The studied traits were number of days to 50% silking (DS), plant height (PH), ear height (EH), ear length (EL), ear diameter (ED), number of rows/ear (RE), number of kernels/row (KR) and grain yield (GY).

Mean square due to locations were significant for DS, EL, KR and GY traits.

The crosses were significant for all studied traits, except PH trait.

Mean square due to lines were highly significant for all traits except PH, EH, and KR.

Mean square due to testers were highly significant for EH and GY.

Also, mean square attributed to lines x testers interaction were highly significant for all traits except for DS, PH, and RE.

The interactions of locations (Loc) with crosses and Loc x lines were highly significant for the studied traits except for PH.

The superior inbred line Ism 6007 had desirable general combining ability (GCA) effects for grain yield and yield components.

Also, the inbred line Ism 7100 showed better GCA effects for PH, EH, ED, RE and GY traits and inbred line Ism 7094 for earliness and grain yield.

The tester SC 128 showed the highest GCA effect for grain yield.

The best crosses for specific combining ability (SCA) effects were Ism 6040 x SC 128, Ism 7094 x SC 128, Ism 7169 x SC 128, Ism 7186 x SC 131 and Ism 7259 x SC 131 for grain yield and cross Ism 6007 x SC 131 for earliness, grain yield, and yield components.

The non-additive gene effects were more important in controlling all studied traits.

Moreover, non-additive gene effects were more interacted by environmental conditions than additive gene effects for all studied traits.

The highest mean values and significant of crosses for grain yield (GY) were obtained from the Ism 6040 x SC 128 (37.5 ard/fad.

), Ism 6007 x SC 131 (37.0 ard/fad.

), Ism 7169 x SC 128 (36.7 ard/fad.

), and Ism 7094 x SC 128 (35.5 ard/fad.

).

These three ways crosses out yielding significant than the commercial hybrids TWC 321 (33.7 ard/fad.

) and TWC 324 (32.5 ard/fed).

These promising hybrids should be tested in advanced trails.