Combining Ability and Heterotic Group Analysis of Several Tropical Maize Inbred Lines from PT. BISI International, Tbk’s Collections

Abstract

Heterotic grouping in maize takes an important role to enhance breeding efficiency. The aim of the research is to analyse combining ability and heterotic group among several tropical maize lines from PT. BISI International,Tbk’s collections. Eighteen S5 tropical maize lines were used as a genetic material. The research was conducted at PT. BISI International,Tbk’s research station, Kediri and Nganjuk, East Java on May until January 2013. Randomized Complete Block Design (RCBD) was used in the experiment with 3 replications. DMRT test was used to determine the better lines. The first experimental results revealed that the lines were significantly different for days to mature; ear length (cm); ear diameter (cm) and 1000-seed weight (g). Based on dendrogam analysis by 3.5 Euclidian dissimiliarity coefficient, the lines can be grouped into 8 groups. Group 1 consists of Sr-1#001 and Loe#242. Loe#057 in group two. Group 3 consists of Sr-1#239; Pron#163; Pron#233; Loe#061 and Loe#055. Group 4 consists of Sr-1#147; Pron#077 and Pron#142. Sr-1#086 and Loe#214 belong to group 5. Pron#026 and Loe#187 belong to group 6. Sr-1#016 and Pron#151 (group 7). Sr-1#247 in the group 8. Pron#077; Loe#055; Loe#057; Pron#142; Sr-1#247; Sr-1#086; Loe#187; Pron#163; and Sr-1#001 were the better lines based on yield potency that potencial to be selected for combining ability and heterosis evaluation. Nine selected tropical maize lines were crossed based on Griffing’s diallel mating design I to generate 9 maternal lines, and 36 F1s and its reciprocal F1s, respectively. The research was conducted across two different locations. The RCBD was used in the experiment with 3 replications. The result of this experiment showed that genotypes x locations effect was significant for all traits except ear length, ear diameter and yield potencial. Additive genetic effect were more important for controlling days to anthesis, days to silking, plant height, ear length ear diameter, moisture content, ear shelling and 1000-grain weight, while non-additive genetic effect were more important for days to harvest, ear weight per plot and yield potencial. Best specific combinations for several important traits were exhibited from parent lines with high x low GCA. The lines showed good heterotic potencial up to 266.20% for heterobeltiosis value. The good GCA lines for yield potencial were Sr-1#001 and Loe#187, Sr-1#001xLoe#055, Sr- 1#247xLoe#055, Sr-1#086xLoe#055, Pron#163xLoe#055, Pron#077xLoe#055, Pron#142xLoe#055, Loe#187xLoe#055 and Loe#057xLoe#055. Best heterobeltiosis was exhibited by Pron#163xPron#142 and Pron#163xPron#077. Based on Dunnet test, the result of third experiment revealed that Sr-1#001xSr- 1#086 (7.49 t/ha), Sr-1#001xPron#142 (7.92 t/ha), Loe#057xPron#142 (7.68 t/ha), Sr-1#001xLoe#187 (8.13 t/ha) and Sr-1#247xLoe#187 (7.64 t/ha) were not significant to BISI816, NK22 and P21, statistically. Sr-1#001xSr-1#086 showed good moisture content traits. Sr-1#001xPron#142 was better than P21 for plant height at Kediri site. Loe#057xPron#142 exhibited better ear girth performance than NK22 across two location, while its ear weight per plot was better than P21 at Kediri site . Sr-1#247xLoe#187 exhibited earlier days to anthesis than BISI816, consistently. The hybrids were potencial to be selected and tested in an advanced hybrids testing program. Combining ability and heterosis analysis, strengthen by yield performance evaluation were used as a basic informations to create heterotic groups. Loe#055, Pron#163 and Loe#187 can be grouped into one heterotic group while the other heterotic group consist of Sr-1#247, Sr-1#001 and Sr-1#086. Pron#077, Pron#142 and Loe#057 can not be grouped into same heterotic group due to low value of breeding efficiency.