Pollen tube behaviour and haploid wheat production via embryo rescue in wheat x maize crosses

Abstract

In wheat, anther culture has been used to a limited extent due to the occurrence of somaclonal variation, aneuploids, albinism and genotype specificity while the crossability loci (Kr1 Kr2 Kr3) are the major limiting factors while crossing with H. bulbosum for haploid production in wheat [1]. Production of haploid wheat plants through wheat x maize crosses was first reported by Laurie and Bennett [2]. Since then, it has emerged as a system of choice for haploid production in wheat. Since maize pollen tube growth and fertilization appear to be insensitive to the crossability alleles of wheat, poly-haploids can be recovered across different genotypes. Wheat x maize system has been shown to be more efficient in haploid production when compared with anther culture [3] or bulbosum technique [4]. The growth of pollen tubes, including abnormalities if any, should be equally emphasized for complete understanding of all the pre-zygotic gametophytic competition in flowering plants [5]. The interaction between pollen and pistil and various pre-fertilization processes affect crossability. Therefore, in this study, an attempt has been made to produce haploids through wheat x maize crosses and to find out the correlation between various pre-fertilization factors viz. pollen germination, pollen tube growth and abnormal pollen tubes with frequency of embryo formation and haploid production.