Comparative pollination efficiency of freshly harvested pollen ofImperata cylindricaandZea maysfor haploid induction in bread wheat

Abstract

Pollen viability is among the critical factors, which determine the success of a doubled haploidy breeding programme, thus the present investigation was undertaken to assess the functional viability and relative longevity of the pollen from Zea mays and Imperata cylindrica for the chromosome elimination mediated approach of doubled haploidy breeding. Two wheat genotypes representing spring and winter ecotypes, namely DH 40 and Saptdhara were pollinated with freshly harvested pollen of two known potential haploid inducing sources, namely Z. mays (grown in polyhouse conditions) and I. cylindrica (wild grass) for 15 and 17 days, respectively, keeping five minutes interval between two subsequent pollinations. The results revealed a significant decrease in the viability of Z. mays pollen up to 95 percent in Saptdhara and 85 percent in DH 40 within one hour, whereas Imperata pollen was found to be functionally viable even at the end of experimentation period, showing high embryo formation in both the wheat parents. I. cylindrica exhibited higher frequencies for haploid induction parameters in both the wheat parents as compared to Z. mays. I. cylindrica pollen, being viable for relatively longer periods than Z. mays can hasten the haploid induction endeavours, thus may be a more efficient alternative to Z. mays for breeding programmes using doubled haploidy technique.

Technology for Production of Wheat Doubled Haploid via Maize Pollen Induction—Updated Review

“…Although I. cylindrica is a noxious weed [58], I. cylindrica is comparable to maize for inducing haploid embryos in common wheat [50]. But I. cylindrica outperforms maize when used in durum wheat, triticale, or their derivatives [59,60]. In practice, I. cylindrica should be handled with care due to its weedy nature.…”

“…The main steps in the Wheat × Maize System are wheat and maize planting, wheat emasculation, maize pollen pollination, hormone treatment, embryo rescue, doubling treatment, and DH plant harvesting (Figure 2). Along the process, numerous factors control the ending wheat DH rate, which is actually attributed to pseudoseed formation frequency (PFF), embryo formation frequency (EFF), haploid regeneration frequency (HRF), haploid formation frequency (HFF), and haploid doubling frequency [59,60,[64][65][66]. However, the inheritance of PFF, EFF, and HRF is independent [61,67], and they can ultimately be reflected in the embryo rate (obtained wheat haploid embryos after crossing and hormone treatment), the plantlet rate (obtained wheat haploid plantlets after haploid embryo rescue), and the doubling rate (obtained wheat DH plantlets after chromosome doubling).…”

Success in Inducing Effective Rooting in Triticale x Wheat and Wheat x Wheat Derived Haploid Plantlets in Cocopeat Mixture

“…But wheat x maize system has also been utilized across the globe being genotype non-specific, yet, it could not draw positive results in wheat-rye and triticale-wheat hybrids. The inquisitive search for more responsive pollinators for chromosome elimination system led Chaudhary et al, (2005) to invent a dynamic Imperata cylindrica-mediated chromosome elimination technique which has not only shown overwhelming success over wheat x maize system in wheat-wheat hybrids (Mayel et al, 2016), but has also recorded a huge success in wheat-rye (Kishore et al, 2012) and triticalewheat hybrids (Badiyal et al, 2014; and durum wheat (Mahato and Chaudhary 2015). Thus, I. cylindrica mediated system has emerged as an efficient alternative to wheat x maize system for DH breeding (Chaudhary et al, 2005;Pratap et al, 2005).…”