Tomato (Solanum lycopersicum) is one of the most important vegetables in the world in terms of nutritional and economic value. The demand for tomatoes is increasing due to the exponential growth of the global population. Given the shortage of arable land and climate change, there is a need to resort to greenhouse production and increasing yields under artificial lighting conditions. Therefore, breeding varieties that exhibit proper growth and yield under artificial light conditions is a new objective in plant breeding. Accordingly, this study aimed to create populations and identify superior combinations from genotypes that responded to LED light (results from a previous study), as well as to select the breeding method and specify the mode of gene action controlling some functional and qualitative traits in tomato plants. Five genotypes from previous research, including three commercial varieties (Sakhia, Hanna, and Hiva) and two pure lines (G16 and G17), were crossbred reciprocally after one generation of selfing. The offspring were eva‎luated in a 5x5 full-diallel genetic design and a randomized complete block design. The results showed that the genotypes had significant genetic diversity in the studied traits, as the genotype effect was significant for all traits. The mean comparison of the genotypes identified the top genotype for each trait. For yield, the top genotype was 10 from the cross between Hanna and Hiva; for fruit number, genotype 26 from the cross between G17 and Hiva; for average single fruit weight, genotype 15 from the cross between Hiva and Hanna; for single fruit weight index, genotype 1 (Sakhia); for pericarp thickness, genotype 22 from the cross between Hanna and G17; for fruit diameter, genotype 34 from Hanna selfing; for fruit length, genotype 17 from the cross between Hiva and G17; for the number of locules, genotype 27 from the cross between G17 and G16; for soluble solids, genotype 9 from the cross between Hanna and Sakhia; and for fruit firmness, genotype 20 from the cross between G16 and Hanna. Correlation results indicated a significant relationship between yield and its components, as well as between fruit diameter and length with pericarp thickness and the number of seed locules. Based on the genetic analysis using Griffing's method, the effects of genotype, parent, and hybrid were significant for functional traits. General combining ability (GCA), specific combining ability (SCA), and reciprocal combining ability (RCA) were also significant. The calculated genetic parameters showed high general heritability for yield and its components, but due to the dominance variance being greater than the additive variance, the specific heritability for the traits was low. Furthermore, since the ratio of general to specific combining ability variance was less than 1, and the Baker’s and Hung and Holland’s ratios were close to zero, the dominance gene effects were greater than the additive gene effects. Considering the general combining ability effects, parent 13 (Hiva) was the best and parent 1 (Sakhia) was the worst among the parents for all traits, while parent 18 (G16) was the best parent for yield. However, based on specific combining ability effects, hybrid 1*23 (the combination of Sakhia and G17) was the most valuable produced hybrid and showed significant positive heterosis compared to the better parent. The second and third best hybrids for yield were 18*13 and 8*13, respectively.

محمدرضا سبزعليان دستجردي , احمد ارزاني

مريم حقيقي

قدرت اله سعيدي , سعيد انصاري مهياري