BOTANY KNOWS TWO PATHS TO FERTILIZATION: self-pollination
Most plants produce hermaphrodite flowers, but plants cannot move or actively choose a partner, instead they have evolved intriguing strategies to prevent self-pollination
and promote cross-pollination.
Earnest Muthomi, an agronomist and a technical director at Kengap, a horticulture consultancy firm, agrees that bees are a vital resource in an avocado orchard."Honey bees are very vital in avocado production because themale and female flower partsof the avocado open at different times of the day affecting self-pollination
Breeding system: The results from pollination experiments showed that fruit set was observed at 15 of 20 bagged capitula for self-pollination
and 18 of 20 untouched capitula for control.
Flower buds were isolated in pre-anthesis using mesh bags, and the subsequent flowers underwent one of four treatments: (1) spontaneous self-pollination--previously bagged fruits were left intact to verify fruit formation (n=35); (2) manual self-pollination
--hand-pollinated using the flower's own pollen (n=65); (3) cross-pollination--hand-pollinated using pollen from different individuals, at least 30 m apart (n=54); (4) open pollination (control)--flowers were marked and left exposed, and the number of fruits formed was recorded (n=145).
Australian researchers have identified a naturally occurring wheat gene that, when turned off, eliminates self-pollination
, but still allows cross-pollination - opening a way for breeding high-yielding hybrid wheat.
Regarding grape pollination, different theories have been proposed, ranging from pollination by wind, insects or self-pollination
, depending on the cultivar.
The tests performed thereon were: spontaneous self-pollination
, hand self-pollination
(geitonogamy), apomixis (by cutting the style with a forceps), cross-pollination, and open pollination (control).
In some cases, the tip of the stigma of sunflower expands above the anthers to get pollens; thus enhancing the probability of self-pollination
. Self-incompatible and cross-pollinated crops need pollinating agents for efficient pollination and seed set (Thapa, 2006).
However, the few studies done so far (which represent only 2.5% of the species) suggest a high incidence of self-compatibility and autonomous self-pollination
(reviewed by Matallana et al., 2010).
Types of crosses included: (1) no hand-pollination to test for automatic self-pollination
Consequently, plants on an island are thought to have generalized pollination modes, i.e., they depend on more than one type of pollinators or are wind pollinated, and many have floral mechanisms than enable autonomous self-pollination
(Barrett et al., 1996).