Genetic Analysis of The Half Diallel Populations of Five Genotypes of Papaya (Carica papaya L.).

Abstract

The increase of papaya production is not followed by quality increment so that cannot meet the consumer’s requirements and taste. One strategy to enhance the development of papaya commercially is the supply of superior cultivars based on consumers taste through papaya breeding program. In order to get an appropriate breeding method, basic informations are essential such as general combining ability (GCA), specific combining ability (SCA), heritability, type of gene action, heterosis, linkage between the characters and influence of the characters associated with the yield. The objectives of this experiment were to study the general combining ability and specific combining ability among five genotypes of papaya, the diversity of fruit quality and yield of ten F1 hybrids, to path-analysis the morphological characters associated with yield potential and fruit quality of papaya. Five S3 papaya genotypes resulted by Indonesian Tropical Fruit Research Institute (ITFRI); BT2, Carmina, Dampit, Carmida and Merah Delima, were used as parents for the development of half diallel populations. Five parents and their ten hybrids were planted at Dramaga field experiment, Bogor, 250 asl altitude, using Randomized Completely Design with three replications. Combining ability was analyzed using Grifting Method II diallel analysis procedure. Variance of analysis all variable observed including vegetative and generative growth, fruit production and quality showed significant difference among genotypes tested. Analysis of variance of GCA and SCA for yield component of variable were very significant difference except SCA for lag phase. The characters of fruit weigth, fruit length, and flesh hardness were controled by additive gene action and Dampit can be selected as parent plant with the best GCA for those characters. The characters of flesh thickness, TSS, fruit number, production per plant and the percentage of abnormal fruit were controlled by non-additive gene action because the efect of SCA and non-additive variance were greater than the efect of GCA and additive variance. Hybrids CarminaXCarmida were heterosis and have the highest SCA and mean for flesh thickness and TSS. Hybrids BT-2 X Dampit, Carmina X Dampit and Carmina X Carmida. have the highest SCA and mean for production per plant. The path analysis result showed the character of leaf width can be used as a marker for highest production, but it cannot be used as selection criteria doe to low of narrow sense heritability. The characters of petiole length and fruit weight can be used as selection criteria for further generation and marker for high production.