สัณฐานวิทยา ความสัมพันธ์ทางพันธุกรรมและการพัฒนาพันธุ์ผักขี้หูด

Abstract

Thai rat-tailed radish was collected from various locations in Chiang Mai Province including the Districts of Doi Saket, San Sai, San Kamphaeng, and Mae On for this research on its morphology and quantitative and qualitative characteristics with the objective to select the plants having best horticultural characteristics for breed improvement. The result showed a diversity of genetic traits. The petal color varies from white to white with purple, and purple. The white with purple petal color is the most common accounting for 69.61 % of the samples. The petiole color is either purple or green, with purple being more prevalent at 58.07 %. Moreover, the stem color shows green, green with purple node, and purple, with green with purple node of stem color being the most predominant forming 66.74 % of all collection. The pod also has a high variation in shape including a pod with deep internode, shallow internode, a short pod with internode, and the long pod with internode, while the average pod length is 12.22 centimeters. Genetic relationships among the Thai rat-tailed radish samples were studied using the RAPD technique. Out of the totally 20 random primers, only five RAPD primers namely OPA09, OPA10, OPC13, OPU06, and OPU16 showed a clear increase in total DNA. A total of 58 bands from these five primers have an average size of 10.4 polymorphic bands per primer with 94.5 % polymorphism. The dendrogram of the genetic relationships showed a high genetic variation in the Thai rat-tailed radish across all collection sites and within a collection site which can be distinguished into nine groups of genetic similarities at 0.69 The self-incompatibility test by evaluation of the pollen tube germination in the style of the five Thai rat-tailed radish samples found that the plant from San Kamphaeng4 (S3), Doi Saket2 (D2) and Doi Saket2 (D4) had self-incompatibility characteristic, which are suitable for use as the maternal line for hybrid production. The Thai rat-tailed radish breed improvement traits had obtained a total of four hybrids for heterosis evaluation which revealed the S2-2-5 x SS2-1-4 progeny having a high heterosis for the traits of total weight, average pod weight, and pod length at 0.41, 29.53, and 7.32 %, respectively.