Sterility, Its Incidence and Causes with Special Reference To Roses

Studies made on a number of crosses between some Hybrid Tea, and Flori-bunda cultivars of garden roses showed the existence of cross-incompatible cultivars. ‘Goudvlinder’, however, was found to be a self-compatible cultivar. In ‘Super Star’ sterility is considered to be genetically-controlled character. The cultivar ‘Una Wallace’ behaved as a highly female-sterile variety.

The percentage hip setting was found to be greatly dependent upon the percentage pollen fertility. Both the hip-setting and pollen fertility showed similar trends of variation in the different crosses made with respect to any one seed-parent. A comparison between the hip-setting capacity of different seed parents on making comparable crosses showed that generally hip-setting capacity was higher in the cultivars which had high pollen fertility.