(go to KOMUGI Home) (go to WIS List) (go to NO.86 Contents)

Wheat Information Service
Number 86: 6-12 (1998)
Research article

Genetic control of supernumerary spikelet in common wheat line LYB

Zheng-Song Peng*, Deng-Cai Liu, Chi Yen and Jun-Liang Yang

Triticeae Research Institute, Sichuan Agricultural University, Dujiangyan City, Sichuan 611830, China


Summary

The supernumerary spikelet(SS) is abnormal spike morphology of wheat (Triticum L.) having additional spikelets per spike. The common wheat (T. aestivum L.) selection, LYB stably showed SS character. Monosomic analysis was used to determine the chromosomal location of genes for the SS character of LYB. F2 monosomic analysis indicated that SS character was controlled by three genes on chromosomes 2A, 2D and 4A. Results also showed that two recessive genes on chromosomes 2A and 4A of LYB promoted the development of SS character, and that a dominant inhibitor of SS on chromosome 2D of Chinese Spring prevented the expression of SS character. These conclusions were confirmed by the data of progenies derived from backcrossing monosomic F1 hybrids to LYB.

Key words: Branched spike, gene localization, supernumerary spikelet, Triticum aestivum, wheat.


Introduction

The normal spike of wheat (Triticum L.) plant has spikelets which attached to the rachis in a distichous pattern. The supernumerary spikelets(SS) character is a genetically conditioned abnormal wheat spike morphology. The term SS, often referred to as branched spike, embraces additional sessile spikelets at a rachis node and additional spikelets on an extended rachilla.

The low kernel weight (Koric 1966) has hindered development of SS cultivars (Yen et al. 1993). However, because SS character conditions additional spiklets, the possibility of utilizing SS character to increase yield of wheat has been suggested (Koric 1966, 1969; Pennell and Halloran 1983; Rawsan and Ruwali 1972; Salunke and Asana 1971). Moreover, it is practical to utilize SS gene to create multispikelet wheat lines (Huang and Yen 1988; Koric 1969; Yen 1965), and multispikelet was regarded as an ideal spike type of high-yielding wheat by breeders (Millet 1983; Yen et al. 1993).

Cytogenetical analysis of SS character development has been conducted in common wheat (T. aestivum L). Sears (1954) observed that plants nullisomic for chromosome 2A or 2D produced twin spikelets, and the arm locations of these genes were identified as 2AL and 2DS. Swaminathan et al. (1966) found that a deletion caused the SS character in a common wheat mutant. Singh and Joshi (1983) found that all ear-branched plants were trisomic (2n=43) in a population containing ear-branching segregates, and the trisome was subsequently identified as 5A (Singh 1986).

It was found that the environmental factors significantly affect the expression of SS in some lines (Sharman 1944; Pennell and Halloran 1984). Fortunately, some lines with stable expression of SS character are obtained, which provide the feasibility to map the genes for SS character. The present study aims to localize the genes for SS character on certain chromosomes in a common wheat line.

Present address: Department of Biology, Sichuan Normal College, Nanchong City, Sichuan 637002, China

-->Next

(go to KOMUGI Home) (go to WIS List) (go to NO.86 Contents)