Breeding of Fruit and Plantation Crops 2 + 1

Pollination pattern and incompatibility

• Self-incompatible fruit cultivars/species need cross pollination for seed/fruit set which includes pollen hydration and germination, pollen tube growth into the style to the ovary, entry into the ovule and embryo sac and release of sperms. Pollination failures may, thus, create barrenness in the tress which is otherwise completely normal in health and free from diseases and insect pests.


• During cross pollination, the sensitive discriminations have to be made between pollen grain of different genotypes for which identity of each pollen is needed.The germination of pollen grain and its penetration into the stylar tissue to reach the embryo sac depends upon acceptability by the pistil which is selective in nature.

Aonla

• In aonla, male flowers appear in clusters in the axil of leaf all over the branchlet while female flowers are on the upper end of a few of these branches.
• Bajpai (1968) reported male to female ratio of 307.9:1 and 197:1 in two successive years indicating marked variation in the expression of sex.
• The maximum number of male flowers opens between 6 and 7 PM and dehiscence of anthers starts soon thereafter.
• The female flowers open in stages and take 72 hours to open completely and the stigma becomes receptive on the third day of anthesis.
• Bajpai (1968) reported that aonla pollen are light and thus the pollination occurs through wind. There is no self-incompatibility in aonla. The cause of poor fruit set may be attributed to a high percentage of staminate flowers.

Apple

• Lal et al., (1972) found 9 apple cultivars completely and 4 partially self-incompatible. For Early Shanburry cultivar, Fanny (54-5%), Winter Banana (60.4%) and Rome Beauty (54.25%) were better pollinizers.
• In Red Delicious, highest fruit set occurred with Jonathan (87.5%) cultivars Mclntosh, Rymer, Jonathan and Rome Beauty set satisfactory crop with self pollen.

Ber

• The majority of flowers are borne axillary on current season growth in clusters. The time of flowering varies in different parts of India.
• Godara (1981) found that cultivars Banarsi, Karaka, Mundia, Murhara, Reshmi, Sandhura, Narnaul, Safeda, Umran, Ilaichi and kakrola were self- incompatible and Umran was found to be the best pollen recipient as well as pollen donor.
• Being sticky, the pollen is transferred mainly by honey bees. Many flowers do not get pollinated at critical stages of gynoecium receptivity and drop off because of a short receptivity period.

Citrus

• Pollen development is normal in citrus except in a few cultivars like Navel oranges, Satsuma mandarin and lime which have no viable pollen.
• In cultivars with abundant pollen, self-pollination occurs but in mixed plantings of different cultivars, cross pollination is not uncommon.
• The stigma remains receptive for 6-8 days. Honey bees are the known pollinating agents. Self-incompatibility has been reported in pummelo, sweet lime and lemon.

Fig

• It is a gynodioecious species. The Capri fig is monoecious while common fig is pistillate.
• The figs commonly grown in India are parthenocarpic and do not require pollination. In other countries, generally Capri figs (wild figs) are planted as pollinizers with the commercial cultivars.
• The cultivars Pune, Black Ischia and Brown Turkey were reported to be Parthenocarpic from Kodur while Turkish White failed to set fruits without caprification

Grape

• Most vinifera cultivars have perfect flowers that have both functional pistil and stamens. Some species of grapes (V.rotundifolia) are dioecious.
• Berry set results from pollination, fertilization and seed development. Some cultivars like Black Corinth set by stimulated parthenocarpy and in others like Perlette, Beauty Seedless, Pusa Seedless, Delight, and Thompson Seedless stenospermocarpy occurs.
• Self pollination is the rule in vinifera grapes. However, cross pollination is also possible and is desirable under certain conditions.

Guava

• Cross pollination is the rule in guava. However, Singh Sehgal (1968) found that self pollination was also predominant and that the possibility of open pollination cannot be ruled out.
• Under open pollination, Allahabad Safeda had the highest fruit set of 85.5 per cent in spring and 84.4 per cent in rainy seasons, while cultivar Sardar reorded 83.3 and 82.2 per cent fruit set respectively.
• Under self pollination, Allahabad Safeda recorded 67.7 per cent fruit set in spring and 66.6 per cent in rainy seasons.

Jackfruit

• In the tropics, flowering and fruiting are continuous throughout the year in the terminal leaf axil of leader and lateral shoots. There appears to be no regular sequence in the incidence of male and female inflorescences.
• Although they are similar during early development, the female is later distinguished by a thicker peduncle and a large annular disc at the anthesis, but later emerged males are smaller.
• Sharma (1964) reported a high degree of sterility with some fruits having 12,000 flowers producing only five fully developed segments surrounded by 448 aborted flowers.
• They also noted partial seed development, suggesting that some might have occurred after fertilization.

Mango

• The panicles bear male and perfect flowers and the cross pollination is mainly done by the house fly.
• The number of perfect flowers per panicle varies between 1000 and 6000. Uniform cross pollination of cultivars Dashehari, Langra and Bombay Green with the pollen of Totapari and of Bombay Green with that of Langra and Chausa, Dashehari and Totapari and of Bombay Green indicated that in nature about 50 per cent of perfect flowers remain unpollinated, stigma remains receptive from one day prior to anthesis with a maximum on the day of anthesis and that fruit set is generally improved by mixed pollination.