Combining ability and heterosis to root-knot nematode resistance on seven genotypes of kenaf using full diallel cross analysis

A full diallel cross is confirmed to be able to advocate kenaf breeders to select breeding materials, such as inbred lines that produce the best combination with heterosis properties. The results of this study provided information about general combining abilities (GCA) of parents, specific combining ability (SCA), as well as heterosis values. This study aims to estimate the combining abilities and heterosis values of root-knot nematodes in kenaf originated from the full diallel cross. Semi-field research was conducted in an experimental garden located at Karangploso Balittas, from November 2018 to January 2019. The variance of GCA values was higher than SCA values for the number of root knot, reproductive factors, and number of egg mass. In contrast, the variance of GCA values was lower than SCA values for the number of second-stage juvenile (J2) and the number of egg per egg mass characters. KR4, K45, and KR15 genotypes indicated negative GCA values on all characters tested. Meanwhile, KR1, Kin2 and DS028 genotypes signified susceptibility with a positive GCA value. The crossbreeding combinations showed negative SCA values on the number of second-stage juvenile, the number of egg mass and the number of egg per egg mass characters of resistance to root-knot nematodes ( M. incognita ), i.e. KR6 x DS028. KR4, KR5 and KR15 genotipe was quite consistent with negative GCA and SCA values, as well as heterosis values for characters of resistance to root-knot nematodes on kenaf roots on the number of second-stage juvenile (J2), the number of egg mass and the number of egg per egg mass characters tested. Genotype of KR4 x KR5 and its reciprocal have negative heterobeltiosis values on number of second-stage juvenile, egg mass, and the number of eggs per egg mass evaluated characters