than 10%,it is grouped as self-pollinated.At least 90%of the progeny is self-pollinated(Mayo,1980) 2)Allogamy(Cross-pollinated,Cross-fertilized Crop Species) The crop species in which the stigma of a flower on a plant is usually pollinated by a pollen from flowers on other plants are grouped as cross-pollinated crops.The extent of cross-pollination varies in different crop species.At least 50%of the progeny is outcrossed(Mayo,1980).The following sex expressions favour cross-pollination. a)Dichogamy Protandry refers to the condition when stamens ripen before stimas. Protogyny refers to the condition when stigmas ripen before stamens. b)Dicliny (Unisexuality) Monoecism refers to the condition wherein male and female flowers are physically separate on the same plant. Dioecism refers to the condition wherein male and female flowers are borne on different plants. 3)Often Cross-pollinated Crops In this group the extent of natural self-pollination is more than 50%while natural cross-pollination (out-crossing)may vary from 10-49%. Classification of Crop Species Crop species are classified as self-,cross-or often cross-pollinated on the basis of natural outcrossing percentage,Table 3.1 lists the important crop species belonging to the three groups described above. Table 3.1 Classification of crop species on the basis of pollination behaviour Self-pollinated crops Rice,wheat,barley,oats,coarse millets (common millet,finger millet,Italian millet, little millet,barnyard millet),lentil,chick-pea,cowpea,French bean,Dolichos bean, groundnut,flax,sesame,soybean,mountain brome grass,tomato,egg-plant,lettuce, apricot,citrus,peach,etc. Cross-pollinated crops Pearl millet,corn,Brassica campestris,sunflower,niger,sunnhemp,Egyptian clover, alfalfa,fenugreek,red clover,white clover,crimson clover,sweet clover,rye-grass, timothy,smooth brome grass,sugar-beet,sugar-cane,cucurbitaceous vegetables, cauliflower,cabbage,spinach beet,amaranthus,garden beet,radish,turnip,carrot, onion,etc. Often Cross-pollinated crops Sorghum,Brassica juncea,castor,safflower,cotton,chili,okra,etc8 than 10%, it is grouped as self-pollinated. At least 90% of the progeny is self-pollinated ( Mayo, 1980) 2) Allogamy (Cross-pollinated, Cross-fertilized Crop Species) The crop species in which the stigma of a flower on a plant is usually pollinated by a pollen from flowers on other plants are grouped as cross-pollinated crops. The extent of cross-pollination varies in different crop species. At least 50% of the progeny is outcrossed( Mayo, 1980).The following sex expressions favour cross-pollination. a) Dichogamy Protandry refers to the condition when stamens ripen before stimas. Protogyny refers to the condition when stigmas ripen before stamens. b) Dicliny (Unisexuality) Monoecism refers to the condition wherein male and female flowers are physically separate on the same plant. Dioecism refers to the condition wherein male and female flowers are borne on different plants. 3) Often Cross-pollinated Crops In this group the extent of natural self-pollination is more than 50% while natural cross-pollination (out-crossing) may vary from 10-49%. Classification of Crop Species Crop species are classified as self-, cross- or often cross-pollinated on the basis of natural outcrossing percentage, Table 3.1 lists the important crop species belonging to the three groups described above. Table 3.1 Classification of crop species on the basis of pollination behaviour Self-pollinated crops Rice, wheat, barley, oats, coarse millets (common millet, finger millet, Italian millet, little millet, barnyard millet), lentil, chick-pea, cowpea, French bean, Dolichos bean, groundnut, flax, sesame, soybean, mountain brome grass, tomato, egg-plant, lettuce, apricot, citrus, peach, etc. Cross-pollinated crops Pearl millet, corn, Brassica campestris, sunflower, niger, sunnhemp, Egyptian clover, alfalfa, fenugreek, red clover, white clover, crimson clover, sweet clover, rye-grass, timothy, smooth brome grass, sugar-beet, sugar-cane, cucurbitaceous vegetables, cauliflower, cabbage, spinach beet, amaranthus, garden beet, radish, turnip, carrot, onion, etc. Often Cross-pollinated crops Sorghum, Brassica juncea, castor, safflower, cotton, chili, okra, etc