การประเมินการเข้ากันได้ของต้นตอทุเรียนพื้นบ้านภาคใต้กับกิ่งทุเรียนพันธุ์การค้า

Abstract

The major obstacle in vegetative propagation by grafting in fruit crops is incompatibility between rootstock and scion. Graft incompatibility may occur sometimes and possibly reduced growth and yield of the scion, leading to economic losses. Two species of durian were studied in this research: Durio zibethinus and D. lowianus. The objective was to study the grafting success of Monthong and Chanee grafted on various indigenous durian rootstocks. The graft union formation after grafting was observed. The phenolic compounds and lignin content above, below and at the graft union were compared. Thecomparison of isozyme peroxidase patterns and shoot growth of Monthong and Chanee on each rootstock were scored. Monthong and Chanee monografts were included as controls. In addition, genetic diversity of each durian rootstocks and scions were analyzed by microsatellite markers. Results showed that at 2 8 days after grafting (DAG), the highest successful grafting was recorded in Chanee grafted on indigenous durian namely Tai Liam, I-som and Lookklom (100%) followed by Chanee grafted on Chanee and Nok rootstocks (96.67%). The graft union were seen as well formed within 28 DAG and notsignificantly differences were found among all grafted plants. At 12 months after grafting (MAG), Monthong and Chanee grafted on Nok and Khamin rootstocks showed good compatibility. The total phenolic compounds and lignin content were analyzed at above, below and graft union. Results revealed significantly higher total phenolic content at the graft union than those above and below graft union in all combinations, while lignin content at above the graft union was higher than other sites. The highest phenolic content was observed at 21 DAG and gradually decrease at 45 DAG. In contrast, lignin content was getting higher at 45 DAG. The peroxidase profiles were analyzed at 12 MAG and visualized by native polyacrylamide gel electrophoresis. Some differences of peroxidase profiles were detected. The identicalperoxidasebandingpatterns from rootstock, scionandatgraft union were observed in 9 grafted combinations: Monthong/Monthong Khamin/Chanee Khamin/Monthong TailLiam/Chanee Lookklom/Monthong, Chanee/Chanee, Chanee/Monthong, Nok/Monthong and Tonkeaw/Chanee. Growth of grafted plants was evaluated during 12 MAG. Results implied that the best combination was obtained when Monthong and Chanee were grafted on Nok rootstock. Genetic variation of 10 samples of durian used as rootstocks and scions was assessed by microsatellite markers with 8 primer pairs. It was found that all 8 primers gave polymorphicbands. Microsatellite amplification showed 1-4 bands (alleles) from each marker with a total of 28 alleles. The genetic distance was analyzed using UPGMA clustering system and 3 groups can be generated with similarity coefficient ranging from 0.56-0.93. It is clearly classified that Nok rootstock is the most genetically distant from other durians used in this study, however good compatibility was obtained between D. lowianus and D. zibethinus.