MEAN PERFORMANCE , HETEROSIS AND COMBINING ABILITIES OF TOMATO CROSSES UNDER SALINE CONDITIONS

Abstract

Field trials were carried out at the Experimental Research Station of Desert Research Center at Ras Sudr , South Sinai Governorate during 2003 and 2004 seasons . This  investigation aimed to improve tomato genotypes for salinity tolerance in SuperMarmand and CastleRock and marketable characters in exotic genotypes LA1673 and LA1963 and Edkawy  the results indicated that  Edkawy genotypes  was superior than the other tomato genotypes in plant height, number of fruits/ plant, number of locules / fruit and total soluble solids in fruit under saline condition. While, the  two local genotypes of tomato SuperMarmand and Castle Rock were earlier and heavier than the other studied genotypes in early yield, average weight / fruit and total yield / plant . The crosses Edkawy × LA 1673 , SuperMarmand × LA 1963 and LA 1673 × LA 1963 recorded positive and significantly heterosis for average fruit weight . Both additive and non-additive gene actions were involved in the genetic control of each plant height, number of fruits/ plant, early yield , number of locules/ fruit, average fruit weight , total soluble of solids ( TSS ) and total yield/plant. Non-additive gene effects were more important than additive ones for all studied characters except average fruit weight and total yield/ plant, where  additive gene effect was more important in the inheritance of both characters . Heritability in broad sense  for all the studied characters were  high and ranged from (64.55%) for total soluble of sugar in fruit to (88.4%) for average of fruit weight. Whereas, heritability in narrow sense was moderate  (39.51%) for total soluble of solids (TSS) and high ( < 50 % ) for the remaining characters under study . Positive and highly significant GCA effects were recorded for plant height and number of locules / plant in Edkawy and LA1673 ; number of fruits / plant , early yield and TSS in Edkawy and castle Rock as well as average fruit weight and total yield / plant in castle Rock and SuperMarmand. The cross Castle Rock × LA 1963 was the heaviest average fruit weight and the followed that cross Edkawy × LA 1673 and Edkawy × Castle Rock were positive and significantly SCA effects. While, the crosses SuperMarMand with each of LA 1673 and LA1963 respectively were positive and significantly SCA effects for total soluble of sugar (TSS). The crosses Castle Rock × SuperMarmand and Castle Rock × LA 1673 were the heaviest grain yield/ plant and highly significant positive for combing ability SCA effect under saline condition in irrigation water at Ras Sudr region.