Genetic Distance Detected with RAPD Markers among Rice Cultivars (Oryza sativa L.) and its Relation to Heterosis
Zhang Peijiang et al (Anhui Academy of Agricultural Sciences, Key Laboratory of Rice Genetics & Breeding Ministry of Agricultural, The P. R. China, Hefei 230031)
Twelve parents were crossed according to NCⅡ design and thirty-two F 1s hybrids were obtained,and Shanyou 63 was as control variety. The heterosis of eight characters, i.e. days of heading, plant height, panicle length and yield components were statistically estimated. The genetic distance (GD) between two parents was evaluated from RAPD banding patterns among parents. The possibility was explored that genetic distance was used to calculate heterosis between two parents. Based on the pair-wise comparisons of amplification products the genetic distance was calculated using Nei's genetic distance and a dendrogram was constructed using an unweighted pair group method with arithmetical averages (UPGMA). The indica and japonica cultivars were easily classified by cluster analysis, and temperate and tropical japonica cultivars were classified into different subgroups,too,but Nuda and javanica cultivars were usually clustered in mixed subgroup. The heterosis of number of grains per panicle was the strongest with a mean 33.5% in relative heterosis (RH) and a mean 23.1% in standard heterosis (SH). Heterosis was compared among three cross-combination groups: J×J, J×J', and J×I. In general, RH and SH showed an order of J×JJ×J'J×I in four characters, i.e. days to heading, plant height, panicle length and number of effective tillers. However number of grains per panicle showed J×JJ×J'J×I in RH and J×JJ×IJ×J'in SH. The GD between two parents were significantly correlated with respective RH and SH in four characters, i.e. days to heading, plant height, panicle length and number of grains per panicle.The results from the dendrogram were found that the economical heterosis between temperate japonica cultivars was low, the heterosis between subgroups was stronger and the heterosis between groups ( indica/japonica) was strongest. Making use of Nuda and javanica, parents of hybrid rice as distinct from ecotype were bred,and super high yield hybrid rice combinations had been bred.
【CateGory Index】： S511