Estimation of heterosis value and genetic distance of some crosses of gogo-dryland and paddy-field rice varieties (Oryza sativa L.)

This study was carried out to estimate heterosis effects on the morphological and agronomical traits in four rice cultivars and their F₁ hybrids as well as to analyze genetic distance of parent cultivars. The research was conducted at the Screen House and Plant Biotechnology Laboratory, Faculty of Agriculture, Brawijaya University, Malang, Indonesia, from September 2017 until February 2018. The parental rice cultivars consisted of gogo-dryland variety, namely, Situ Bagendit and Towuti, and paddy-field variety, namely, Ciherang and Cibogo. The F₁ hybrids were F₁ SBCH, F₁ SBCB, F₁ TWCH and F₁ TWCB. Data were accomplished by single plot design method on morphological traits i. e. plant height, leaf number and panicle length, and agronomical traits i. e. number of tillers, number of productive tillers, heading date, harvest date, weight of 100 grains and grain yield. To analyze genetic distance, four primers i. e. RM219, RM260, RM525 and RM318 were employed. The results showed that all F₁ hybrids tended to exhibit negative heterosis value. The estimates of heterosis, relative to mid-and high-parental values reflected desirable effect with negative signs on all F₁ hybrids for the character of plant height and heading date. Meanwhile, only F₁ TWCB exhibited negative heterosis for harvest date, and only F₁ SBCH showed positive heterosis value for panicle length. On the contrary, the rest of studied characters gave negative heterosis values. Furthermore, the genetic distance was found not to have any relationship with heterosis since all F₁ hybrids had negative heterosis values regardless of their respective parent’s genetic distance values.