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Wheat Information Service
Number 95: 1-4 (2002)
Research article

Monosomic analysis of genie male-sterility in hexaploid wheat

Dalmir Singh and P.K. Biswas

Division of Genetics, Indian Agricultural Research Institute, New Delhi 110012, India

Summary

Partial genie male-sterility (p-mst) caused by the conversion of anthers into ovaries, was isolated from F3 population of a cross involving Sel.212 and variety HD 2009. The inheritance study has revealed its control by a single recessive gene. An attempt was made to locate the gene on specific chromosome using monosomic lines of cv. Chinese Spring. Detailed monosomic F1 and F2 analysis has pointed out the involvement of two independent genes located on chromosomes 4A and 6B, respectively.

Key words: genie male-sterility, monosomics, Chinese Spring, hexaploid wheat, gene location

Introduction

Genic male-sterility (g-mst) is controlled by nuclear gene whose action is not influenced by cytoplasmic factors. Therefore, the inheritance pattern and expression of the sterility are entirely Mendelian. It exhibits no reciprocal differences and is controlled by recessive genes in the majority of the cases.

Genie male-sterility (g-mst) has been reported in major crops (Kaul 1988). Generally g-mst is of spontaneous origin. In Triticum aestivum it has, been reported by Pugsley and Oram (1959), Lupton and Bingham (1966-67), Athwal et al. (1967), Krupnov (1968), Lemekh et al. (1971), Jan (1974), Xiangmin and Herong (1981) and Deng and Gao (1982). Recently a novel genie male-sterility was reported by Singh (2002) where the male-sterility was incomplete, therefore, it was designated as p-mst (partial genie male sterility). The inheritance study was carried out which revealed its control by single recessive gene (Singh 2002).

In the present study, an attempt has been made to locate ms gene on specific chromosome of partial genie male sterile (p-mst) strain.

Material and methods

The partial genie male-sterility strain of T. aestivum (2n=42) from the Department of Genetics, IARI, New Delhi was considered appropriate for locating gene conditioning genie male-sterility. For this purpose monosomic analysis was employed. The 21 aneuploid lines of cv. Chinese Spring used were originally produced by Sears (1954).
The salient features of p-mst strain and cv. Chinese Spring: p-mst stock evolved from Selection 212 (monosomic 5B Chinese Spring / Rye // Sonalika) /// HD 2009. This strain is characterized by full awning, single gene dwarf, late maturing, resistant to stem and leaf rusts of wheat. It produces 10 to 12% selfed seeds which are sufficient for its maintenance. The seeds formed on p-mst plant are dented or notched on its sides. Cv. Chinese Spring an awnless and hooded spring wheat, susceptible to rusts.

Seeds of monosomic (2n=41) plants were planted in the field. At appropriate stage of meiosis, monosomic plants were identified cytologically at first meiotic metaphase. The monosomic plants were crossed with p-mst strain as female parents. A cross was also made with disomic parent. All the crossed seeds were planted in the field and monosomic F1 hybrids were identified cytologically from all the 21 lines. F2 seeds were harvested from all the monosomic F1 hybrids and also from disomic cross and F2 populations were raised. Data were- recorded on agronomic traits from all the monosomic and disomic F1 hybrids and F2 plants.

A chi-square test was applied to the segregation ratios of both the sterile and fertile F2 plants of disomic cross and F1 monosomic hybrids. The disomic cross provided the data of the conventional genetic analysis and among the F2's derived from monosomic F1's, only those lines which deviated from the expected ratios were considered to be the critical lines (chromosomes on which the fertility/fertility genes are located).

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