Rice Novel Semidwarfing Gene d60 Can Be as Effective as Green Revolution Gene sd1.

Motonori Tomita,Keiichiro Ishimoto

doi:10.3390/plants8110464

Motonori Tomita, Keiichiro Ishimoto

Open Access

https://doi.org/10.3390/plants8110464

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Abstract

Gene effects on the yield performance were compared among promising semidwarf genes, namely, novel gene d60, representative gene sd1 with different two source IR8 and Jukkoku, and double dwarf combinations of d60 with each sd1 allele, in a Koshihikari background. Compared with the culm length of variety Koshihikari (mean, 88.8 cm), that of the semidwarf or double dwarf lines carrying Jukkoku_sd1, IR8_sd1, d60, Jukkoku_sd1 plus d60, or IR8_sd1 plus d60 was shortened to 71.8 cm, 68.5 cm, 65.7 cm, 48.6 cm, and 50.3 cm, respectively. Compared with the yield of Koshihikari (mean, 665.3 g/m2), that of the line carrying Jukkoku_sd1 allele showed the highest value (772.6 g/m2, 16.1% higher than Koshihikari), while that of IR8_sd1, d60 and IR8_sd1 plus d60, was slightly decreased by 7.1%, 5.5%, and 9.7% respectively. The line carrying Jukkoku_sd1 also showed the highest value in number of panicles and florets/panicle, 16.2% and 11.1% higher than in Koshihikari, respectively, and these effects were responsible for the increases in yield. The 1000-grain weight was equivalent among all genetic lines. Except for the semidwarf line carrying Jukkoku_sd1, semidwarf line carrying d60 was equivalent to line carrying IR8_sd1in the yield of unpolished rice, and yield components such as panicle length, panicle number, floret number /panicle. Therefore, the semidwarfing gene d60 is one of the best possible choices in practical breeding.

Highlights

Semidwarfing prevents plants from lodging at their full-ripe stage, making them lodging-resistant to wind and rain, enhances their adaptability for heavy manuring and markedly improved the global productivity of rice and wheat between 1960–1990 [1,2]
The full length in lines carrying one or two semidwarf genes was already shorter than that of Koshirikari lines at the time of transplanting (June 7, 28 days after sowing), and the differences became prominent around 64–70 days after sowing (July 13 and 19) (Figure 1, Table 1)
As exemplified by IR8, which was the variety behind the Green Revolution, many of the rice

Summary

Introduction

Semidwarfing prevents plants from lodging at their full-ripe stage, making them lodging-resistant to wind and rain, enhances their adaptability for heavy manuring and markedly improved the global productivity of rice and wheat between 1960–1990 (up to double yields of rice and quadruple yields of wheat) [1,2]. Semidwarf rice contributes stable production in the monsoonal regions of Asia, where typhoons frequently occur during the yielding season and brings benefits such as erect leaf angle, reduced photoinhibition, and possibility to plant at higher densities to japonica varieties grown in California and in South America [3]. In Japan, semidwarf cultivars in the Kyushu region were developed in the 1960s using the native semidwarf variety Jukkoku [4]. In the Tohoku region, semidwarf cultivars were developed in the 1970s using the semidwarf mutant Reimei induced by Fujiminori-gamma-ray irradiated [5]

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