Characterization and Heterosis of High Quality Resistant Glutinous Rice Germplasms

  Objective  In order to improve the yield, quality and resistance of traditional glutinous rice varieties, and meet the development demand of special glutinous rice market.

  Method  Glutinous rice germplasms of high yield, disease resistance, low amylose content (AC), and high alkali spreading value (ASV) were evaluated and identified. Using the incomplete diallel crossing(NC II) method, the selected parental lines and 20 hybrids were pooled to construct a matrix for breeding evaluation.

  Result  The actual yields of 7 choice germplasms ranged from 7744.35 to 9216.45 kg·hm⁻², among which X-104 had the highest real cut yield of 9216.45 kg·hm⁻² and X-27 had the highest real cut yield of 8960.40 kg·hm⁻², which were significantly higher than those of the 3 reference varieties. The abovementioned two short and stout cultivars respectively carried Pi-1 and Pi-k^h and Pi-1, Pi-9, and Pi-k^h genes were moderate resistance to rice blast. They had AC of 1.71% and 1.68% as well as ASV of 6.75 and 6.13, respectively, indicating low gelatinization temperature. For heterosis in breeding, X-27 exhibited a combining ability of higher on grain yield and quality in addition to taller on plant height; X-57 of greater on yield and ASV but lower on plant height and AC; and X-104, despite the high grain yield and quality, did not offer meaningful advantages. Among the hybrids, Minnuo 2S/X-41 and Minnuo 2S/X-107 were significantly superior to their parents in terms of grain yield, plant height, AC, and ASV.

  Conclusion   The determination of grain yield and quality of glutinous rice involves numerous factors such as effective panicle number, panicle length, 1000-grain weight, length-to-width ratio, yield per plant, AC, and ASV. The broad heritability (h²_B) of such traits of the parents and hybrids in this study ranged between 14.72%–53.99%, and the narrow heritability (h²_N) between 10.25%–43.07%. The relatively low indexes indicated instability and being prone to environmental effects in gene transfer from generation to generation. Consequently, breeding glutinous rice targeted for a specific use would require a complicated process of selection and hybridization.