インドネシア産イネの bulu と tjereh 群における脱粒性, 離層組織およびエステラーゼ同位酵素遺伝子型の関係について

抄録

Using 58 bulu and 54 tjereh rice cultivars of Indonesia, relationship among degree of grain shedding, histological peculiality of abscission region and esterase zymogram were investigated. The results obtained were summarised as follows. 1. The breaking tensile strength of a variety varied from 86 to 249 g in bulu type rice and from 51 to 220 g in tjereh type rice, the average being 180±36 g in the former and 107±41 g in the latter. The strength of 39 out of 57 cultivars in the bulu type rice (68.4%) was larger than 171 g, while the strength of 44 out of 50 cultivars in the tjereh type rice (88.0%) was smaller than 170 g. Especially, the strength of about two-thirds in the latter was smaller than 110 g (Table 1). 2. Both of bulu and tjereh type rices, excepting one cultivar in the former and two cultivars in the latter, had abscission layer. In most tjereh type rice cultivars (90.0%), parenchymatous cells in the abscission layer cracked completely at harvest time, whereas no cracking occurred at the harvest time in most bulu type rice cultivars (93.0%) (Table 2). 3. As to the esterase isozymes, four genotypes of 1 (Est₁ Est₂^S Est₃^F), 3 (Est₁ Est₂^F Est₃^F), 6 (Est₁ Est₂^O Est₃^S) and 8 (Est₁^O Est₂^S Est₃^S) were found commonly in both bulu and tjereh type rices. Additionally, genotype 12 (Est₁^O Est₂^O Est₃^F) was found in the bulu type rice, while genotype 9 (Est₁^O Est₂^F Est₃^F) was found in the tjereh type rice. According to Nakagahra, the esterase genotype 1 corresponded well to the majority of Indian varieties (Indica), genotype 3 to that of southern China (Sinica), genotype 6 to that of the nothernmost areas (Japonica). Genotypes 8 and 12 are representatives of hill and mountain rice in Southeast Asia (Javanica). In the bulu type rice, the proportion of cultivars belonging to the genotypes of 6, 8, 12, 1 and 3 was 79.3%, 10.3%, 6.9%, 1.7% and 1.7%, respectively. In the tjereh type rice, on the other hand, the number of cultivars to genotypes of 3, 1, 6, 8 and 9 was 43.8%, 39.6%, 8.3%, 6.3% and 2.1%, respectively (Table 3). 4. In the bulu type rice, number of cultivars having "hardly shedding-uncracking abscission layer- Est₁ Est₂^O Est₃^S" was largest (78.9%), and next was those having "hardly shedding-uncracking abscission layer-Est₁^O Est₂^S Est₃^S" (7.0%). In the tjereh type rice, the proportion of cultivars having" easily shedding - cracking abscission layer - Est₁ Est₂^F Est₃^F" and those having "easily shedding - cracking abscission layer - Est₁ Est₂^S Est₃^F" was 41.9% and 39.5%, respectively (Table 4). Judging on these three characteristics, bulu type rice was similar to Japonica type rice.