Cytogenetic and crossability studies in hulled wheat collected from Central Zagros in Iran

Underutilized hulled wheat species may be valuable sources of genes for wheat improvement. Hulled wheats of mountainous Central Zagros area of Iran are poorly studied with unclear classification status. In this study, the region was extensively searched and hulled wheats were sampled from local farmers’ fields. Cytogenetic studies of several samples revealed that these wheats are tetraploid with a chromosome number of 2n = 28. Considerable level of karyotypic resemblance was detected between these hulled wheats and durum wheat genotypes, suggesting their genomic similarity. To compare the degree of cross compatibility, F1 progenies were produced using three durum accessions and a bread wheat cultivar as female parent in crosses with two of the collected hulled wheat samples, namely Zarneh and Jonghan. The highest crossability rate was observed when Aria, a durum wheat cultivar, was used as female parent. In general, Jonghan showed higher crossability rate with both bread and durum cultivars as compared to Zarneh. The meiotic behavior of F1 genotypes was analyzed to determine genomic characteristics of hulled wheat samples. Microscopic examination of pollen mother cells at meiotic metaphase strongly suggested the AABB type genome for the hulled wheat samples. Meiotic behaviors of hybrids derived from cross with Zarneh as male parent showed more abnormalities than the other male parent. Meiotic restitution, chromosomes laggards and chromosomal bridges were noticed and the extent varied for each cross. It may be concluded that the hulled wheats of Central Zagros that are currently cultivated are mainly tetraploids emmer containing AABB genome and are crossable with durum wheat, producing hybrids mostly with normal meiotic behaviors.