Soonthree Surson, Suvit Loahasiriwong, Preecha Prathepha, and Sophon Wongkeaw

pp. 139 - 152

Abstract

There are many important steps in breeding for rust resistant groundnut cultivar e.g. evaluation of
resistance levels, and population building. Groundnut is self-pollinated crop, it has a high rate of self- pollination in the breeding program. The use of DNA to classify hybridization would help to make more accurate
selection and speed up the progress of work. The population of this study was from crosses of susceptible
cultivars (KKU1 and Tainan 9) and resistant cultivar (NC Ac 17090). It was found that in F₁, hybrids had
many characteristics in between the parentsícharacters. For example, hybrid of Tainan 9 × NC Ac 17090 had
no difference from Tainan 9 in seed weight per plant, width and length of pod, but pod per plant and pod
weight per plant had higher values than those of Tainan 9 (high yield cultivar). However, hybrid of KKU2 × NC Ac 17090 had seed weight per plant, width and length of pod values in between those of parents e.g. lower
than KKU 1 but higher than NC Ac 17090.
From RAPD technique, 120 primers have been screened. Only one primer (OPO11) showed a difference between NC Ac 17090 and susceptible cultivars (KKU1 and Tainan 9) at 1000 base. So, it was introduced
as a tool to select F₁ hybrid. The results indicated that F₁ hybrids were 56.25 and 57.69% from crosses of
Tainan 9 × NC Ac 17090 and KKU 1 × NC Ac 17090 respectively. Results from morphological study confirmed
that those plants were from hybridization. Correlation of pustule diameter and number of pustules were
significant. Results from F₂ indicated that the ratio of susceptible to resistant plants was 15: 1 (p>0.05). However, only 50% of plant with small pustule showed O11₁₀₀₀ maker.