A partial male sterile rice plant (Oryza sativa L.)–cytogenetics of multivalent chromosomal associations

A partial male sterile plant of spontaneous origin was isolated from a traditional tall rice variety Singhawar. The cytological observations of male sterile plant suggested that chromosomal irregularities such as abnormal chromosome number, chromosomes not arranged properly at metaphase plate, chromosomal fragments at pollen mitosis, and high frequency of quadrivalents (1_IV + 10_II, 2_IV + 8_II and 3_IV + 6_II) and trivalent associations in meiocytes probably caused male sterility. The multivalent associations combined with aneuploidy in the pollen mother cells of selfed progenies caused high pollen sterility.