Relative efficiency of different Gramineae genera for haploid induction in triticale and triticale x wheat hybrids through the chromosome elimination technique

Abstract

The study was undertaken to evaluate the relative efficiency of different Gramineae genera for haploid induction in triticale (xTriticosecale) and triticale x wheat (Triticum aestivum) hybrids through the chromosome elimination (wheat x maize, Zea mays) system. Eight intergenotypic triticale and 15 triticale x wheat crosses were subjected to hybridization with nine different Gramineae genera viz., Z. mays, Sorghum bicolor, Pennisetum americanum, Setaria italica, Festuca arundinacea, Imperata cylindrica, Cynodon dactylon, Lolium temulentum and Phalaris minor in two separate experiments. This was followed by in vivo auxin treatment of the crossed spikes and subsequent rescue of the haploid embryos to regenerate green haploid plantlets. All the triticale and triticale x wheat crosses resulted in seed set in variable frequencies when hybridized with maize, I. cylindrica, pearl millet and sorghum. Seed set was also obtained with S. italica, F. arundinacea and P. minor in a few crosses in both groups. In general, all the triticale x wheat crosses, except for one in each case, resulted in embryo formation and green haploid plantlet regeneration when hybridizations were carried out with maize and I. cylindrica. However, the latter outperformed the former in embryo formation (25.48% vs. 20.0%) and regeneration (34.17% vs. 15.10%) frequencies, the differences being significant for regeneration frequencies. In the case of triticale hybrids, no significant differences between maize and I. cylindrica were observed for the three parameters of haploid induction. Embryo formation and regeneration were also observed in some of the triticale as well as triticale x wheat F 1 hybrids when hybridized with sorghum and pearl millet.

Production of dihaploids in durum wheat using Imperata cylindrica L. mediated chromosome elimination

“…However, the unsynchronized flowering of these 2 species complicates the hybridization process. Chromosome elimination via Triticum aestivum L. × Imperata cylindrica L. interspecific hybridization, which was first reported by and Pratap et al (2005), is a relatively new and promising technique. Imperata cylindrica L. is actually a perennial invasive weed that synchronously blooms with wheat.…”

“…On the other hand, obtaining higher percentages of haploid regenerants from all the studied species proved that this technique, unlike the others, is not genotypespecific . Imperata cylindrica L. mediated chromosome elimination has been applied to date only on the species Triticum aestivum L. Pratap et al, 2005;Komeda et al, 2007;Tayeng et al, 2012) and Triticum aestivum L. × Secale cereale L. hybrids (Kishore et al, 2011). Therefore, the objective of the present study was to evaluate the possibility of obtaining dihaploid durum wheat (Triticum durum L.) plants by interspecific hybridization with Imperata cylindrica L.…”

Cytological evidence for chromosome elimination in wheat * Imperata cylindrica hybrids

“…Recently, it was reported that wheat haploids are formed by crossing with I. cylindrica, a wild grass remotely related to wheat Pratap et al, 2005). This novel haploid induction method has two great advantages in practical application, (1) high frequency of haploid induction irrespective of wheat genotypes, and (2) natural coincidence of flowering period of wheat and I. cylindrica under subtemperate condition.…”

“…In addition, the coincidence of flowering period between wheat and I. cylindrica enables us to obtain fresh pollen of I. cylindrica freely. From these points, I. cylindrica is expected to be employed in wheat haploid production alternative to maize Pratap et al, 2005) Wheat haploid induction using I. cylindrica pollen has been reported only in India so far Pratap et al, 2005). I. cylindrica is merely a wild grass and therefore has uneven genotypes (Matumura et al, 1983;Matumura and Nakajima, 1988;Cheng and Chou, 1997), which does not ensure that I. cylindrica distributed in other regions can induce wheat haploid.…”

“…This novel haploid induction method has two great advantages in practical application, (1) high frequency of haploid induction irrespective of wheat genotypes, and (2) natural coincidence of flowering period of wheat and I. cylindrica under subtemperate condition. Wheat genotypes affect the crossability with alien species (Inagaki and Mujeeb-Kazi, 1995;Pratap et al, 2005). For example, wheat varieties with dominant Kr genes, which inhibit alien pollen tube growth, show greatly reduced crossability with many alien species (Riley and Chapman, 1967;Snape et al, 1979;Kasha, 1981, 1983;Sitch et al, 1985).…”