Heterosis And Inheritance Of Productive Characters In Tomato (Lycopersicon Esculentum Mill.)

The present study was conducted to evaluate some tomato varieties(Lycopersicon esculentum Mill), on the 1/2P(P+1) Diallel Data studied the heterosisfor 10 yield relative characters and estimate general combining ability (gca) forparents and specific combining ability (sca) for their hybrid combinations and geneticcorrelation.1 Five different parents and their hybrid combinations add up to 15genotypes, SAS (statistical Analysis System, version 9) and DMRT (Duncan'sMultiple Range Test) were applied to estimate heterosis percentage, general andspecific combining ability and their significant difference in addition hybridcombinations performance for different trait and genetic correlation were significantlytested. The results were summarized as follows:1.1 The analysis of heterosis indicate that all yield relative characters oftomato was quite extensive, plant yield showed strongly evident positive heterosis aswell as fruit weight, fruit number, leaf chlorophyll content, fruit set time and fruitvertical diameter, others four yield relative characters had the same level of heterosis,on the other hand fruit weight showed strongly positive heterosis over high parent,fruit vertical diameter, fruit vertical/across diameter and plant yield also showed positive heterosis over high parent. Heterosis degree of different characters wasdifferent. The standard deviation of different crosses was different.1.2 General combining ability (gca) and specific combining ability (sca)estimated were significantly differ for all characters except flower number, It'sindicated that this yield relative characters was influenced by the add effect or non-add effect of gene or both ones. Among all parent B was superior in generalcombining ability for fruit number, fruits set percentage, fruit vertical/across diameterand leaf chlorophyll content, while D was superior among all parents for fruit weight,plant yield, fruit across diameter and fruit vertical diameter, so we can consider it inbreeding. Although, according to general combining ability, parent D was the highestfor the most characters and specific combining ability showed that A×D hybrid wasthe best for all important characters, other parents still, could be use successfully toutilize heterosis for other yield relative characters in cultivated tomato.2 We chose 15 genotypes of tomatoes to analyze the genetic correlation of10 yield relative characters, and the results showed:The genetic correlations between different yield relative characters showed nonsignificant different between fruit vertical/across diameter with other characters. Fruitnumber also had high positive correlated with fruit set percentage, leaf chlorophyllcontent and fruit set time the correlation coefficient were (0.9677, 0.5164 and 0.7002,respectively). Fruit set percentage had positive correlated with fruit set time and plantyield the correlation coefficient were (0.6868 and 0.5279), respectively. Fruit set time had positive correlation with plant yield, the correlation coefficient was 0.5836. Fruitweight had highly positively correlated with plant yield, fruit across diameter and fruitvertical diameter and the correlation coefficient were (0.7208, 0.9832 and 0.8898respectively). Plant yield also was positively correlated with fruit across diameter andfruit vertical diameter (0.7208 and 0.7299).To increase tomato yield through breeding program attention should be madeto improve fruit weight, fruit number, fruit set percentage, plant yield and otherrelative characters.