Combining Ability Analysis for Yield and Resistance to Pepper yellow leaf curl Thailand virus in Chilli Pepper (Capsicum annuum L.)

Abstract

    The pepper yellow leaf curl Thailand virus (PepYLCTHV) is one of economic importance as it has a negative impact on chili pepper production. The use of chilli pepper resistance to PepYLCTHV is a sustainability strategy for controlling the disease. Therefore, the objective of this experiment was to study about the combining ability of pepper varieties with regard to yield and resistance to PepYLCTHV. Thirteen F₁hybrids testcrosses were obtained by testcross mating design, and they were compared with 14 parental lines and a susceptibility check (KM-P13001-4). The study was of randomized complete block design (RCBD) with three replications and five plants per replication. The results showed that the Khaekdam varieties had the highest general combining ability (GCA) value for fresh yield characteristics and dry yield at 170.43 and 54.84, respectively. For the GCA value of pepper yellow leaf curl virus disease, the Huareua-7 variety showed the lowest value at -1.54, which was suitable for development of a tolerant variety. Four F₁-hybrids, KM-P13052-10-2 x 9853-123, KM-P13052-8-2 x 9853-123, Yodsonkem 80 x 9853-123 and PP0537-7504 x 9853-123 showed the highest heterosis values in fresh yield base on %MP as 148.98%, 257.96%, 46.56% and 68.63%, respectively. %HP were 140.60%, 239.47%, 23.08% and 45.76% respectively. However, all 13 hybrids showed susceptibility to the disease, so it was concluded that resistance to chili pepper disease was controlled by a recessive gene. In addition, the Huareua-7 x 9853-123 hybrid showed the lowest disease level score of 3.3, and the lowest percentage heterosis of -28.57. The results suggest that this hybrid is suitable for the development of chilli pepper varieties that are resistant to the PepYLCTHV virus.