COMPARATIVE GROWTH AND FUNCTION OF NORMAL AND DEFICIENT POLLEN IN A SUBSTITUTION MONOSOMIC OF CHROMOSOME 3D IN WHEAT

Normal pollen with chromosome 3D from Red Bobs had little competitive advantage over pollen deficient for chromosome 3D when a substituted monosomic line of wheat derived from the hybrid Rescue × Golden Ball was selfed. Although the initial rate of pollen tube growth of the 21-chromosome pollen was greater than that of the 20-chromosome pollen, ultimately the two kinds of pollen functioned in the proportions in which they were formed. The 21-chromosome pollen of the substitution monosomic had an advantage over 20-chromosome pollen in a cross with monosomic 3D of Red Bobs, but not with three other 3D monosomic varieties. However, normal pollen in all the reciprocal crosses showed a competitive advantage, affecting fertilization in up to approximately 90% of the cases. Thus chromosome 3D in the Rescue – Golden Ball medium gives the normal pollen little competitive advantage.