Breeding for Outcrossing Ability in Rice, to Enhance Seed Production for Hybrid Rice Cropping

Abstract

Background: Adoption of the hybrid rice varieties by farmers is often impaired by the high price of hybrid seed, due to low yields in hybrid seed production fields. Female outcrossing ability (FOA) and female hybrid seed production ability (FHSPA), defined as the rate of filled spikelets of the male sterile (MS) line and as its grain yield under outcrossing, respectively, determine plant traits for hybrid seed yield. Breeding for FOA and FHSPA in rice has suffered from the lack of a high throughput phenotyping method and the inbred breeding approach used for the development of MS lines. We developed an innovative hybrid rice breeding strategy that uses the monogenic recessive male-sterility gene ms-IR36 for the reciprocal recurrent improvement of maintainer and restorer populations.

Grain shape is a factor affecting the stigma exsertion rate in rice

“…Cultivated rice lost the outcrossing ability during domestication ( Parmar et al., 1979 ; Marathi et al., 2015 ). MSLs of hybrid rice need to restore the outcrossing ability to meet the needs of hybrid seed production ( Taillebois et al., 2017 ). The stigma exsertion of rice breaks through the closure of palea and lemma, prolongs the pollination period, compensates for the asynchronous flowering time of male and female parents, and thus improves the outcrossing ability of MSLs ( Rahman et al., 2017a ; Zou et al., 2020 ).…”

Potensi Hasil Benih Padi Hibrida pada Tiga Galur CMS dengan Sumber Sitoplasma yang Berbeda

“…Tetua betina (CMS) dan tetua jantan restorer memberikan pengaruh yang nyata terhadap hasil benih padi hibrida yang dihasilkan (Tabel 3). Keterangan: Angka yang diikuti oleh huruf yang sama pada kolom yang sama tidak berbeda nyata berdasarkan uji beda nyata jujur (BNJ) pada α = 5%; ** = berpengaruh nyata pada α = 1%; KK = koefisien keragaman dipengaruhi oleh morfologi bunga tanaman dan karakter pembungaan galur tetua (Widyastuti et al, 2016), sehingga berpengaruh terhadap outcrossing yang dapat menentukan pengisian gabah pada CMS yang diserbuki oleh restorer (Taillebois et al, 2017). Dengan demikian, tingkat produksi benih padi hibrida dipengaruhi oleh penggunaan CMS dan restorer yang disilangkan.…”

QTL Fine Mapping of a Novel Genomic Region Associated With High Out-crossing Rate Derived From Oryza Longistaminata and Development of New CMS Lines in Rice, O. Sativa L.

“…However, low hybrid seed production due to the poor out-crossing rate of the female parent is one of the major constraints that not only limits hybrid rice development but also its adoption in rice farmers' elds in Asian countries (9.40% in Vietnam, 6.80% in Bangladesh, 4.30% in the Philippines, 3.20% in India, and 0.50% in Indonesia) (Barclay 2010). Hence, increasing the out-crossing rate represents priority research for hybrid seed production (Taillebois 1983;Taillebois et al 2017). Despite many efforts for genetic improvement of out-crossing rate in hybrid seed production, there is no clear advancement yet, such as improvement of stigma traits in hybrid parental lines and higher out-crossing rate.…”

“…area, stigma breadth, and pistil length(Virmani and Athwal 1973;Zhou et al 2009;. It was revealed that these oral traits were positively correlated with a higher out-crossing rate(Kato and Namai 1987a;1987b;Miyata et al 2007;Liu et al 2015;Taillebois et al 2017). Especially, seed setting rate is highly in uenced by stigma exsertion in male sterile plants(Parmar et al 1980;Hoff and De La Torre 1981) and long stigma is regarded as the major factor for high stigma exsertion…”