Breeding and application of a new two-line super rice variety Guiliangyou 2 for early/late-cropping dual-usage.

【Objective】The present study was conducted to breed early/late-cropping dual-usage super rice variety with strong heterosis, high yield, wide adaptability in order to provide supports on high-yield, stable yield and food safety production in Guangxi. 【Method】In 2004 a self-bred photo-thermo sensitive genic male sterile line Guike-2S, and a strong restoring line with wide compatibility Guihui 582, was crossed to obtain Guiliangyou 2, followed by investigating its comprehensive trait performances in variety comparative test in 2005, and Guangxi regional trial and producing tial of early season late-maturing rice group during 2006-2007. 【Result】Guiliangyou 2 has characteristicss of strong heterosis, high yield, stable yield, wide adaptability, etc. Its growth duration was 121 and 116 days at early and late cropping, respectively. The variety was charactered by 116 cm of plant height, 160 grains per panicle, 88% of seed setting rate and 22.0 g of 1000-grain weight. The yield of Guiliangyou 2 was 8797.5 kg/ha in variety comparative test in 2005, which was increased by 6.30% as compared to the control Teyou 63. In Guangxi regional trial and producing trial during 2006-2007,the average yield of Guiliangyou 2 were 8646.0, 8281.5 and 8389.5 kg/ha, which were increased by 9.17%, 8.44% and8.10% compared with the control Teyou 63, respectively. During early cropping high-yield demonstration test(6.67 ha) in Luchuan county of Yulin city in 2007, the average yield of Guiliangyou 2 in high-yield, moderate-yield and low-yield fields was 11110.2 kg/ha. In super rice double-cropping high-yield demonstration test(6.67 ha) in Luchuan county of Yulin city in 2012, its total yield of early-and late-cropping was 21380.1 kg/ha with an average of 10690.1 kg/ha.【Conclusion】Guiliangyou 2, the first self-bred super rice variety with better application prospect, is suitable for planting as early and late rice in south regions of Guangxi, and as single early cropping rice or a middle-season rice in middle and north regions of Guangxi.