Pollen and pollination experiments. I. the contribution of stray pollen to the seed set of depetalled,hand-pollinated flowers of apple

Summary Using the finger nails to remove most of the petals is a fast method of preparing apple flowers for hand pollination in the balloon stage. Such flowers still appeared quite attractive to insects; left to open pollination, the seed set per flower averaged two thirds of that of similarly treated, but hand-pollinated flowers. With the aid of marker pollen of scab or mildew resistant donors and the subsequent screening of the seedling progenies for resistance, it was shown that the stray pollen was responsible on average for one of every three seeds formed by unbagged depetalled and hand-pollinated flowers.     

球花石斛人工授粉试验

试验表明球花石斛通过人工异花授粉才能结实,同株异花在开花后第3、5、10 d授粉的座果率依次为43%、52%、15%,异株异花相同时间授粉的座果率依次为45%、54%、18%,两者座果率差别不大;花开后第3～10 d都能人工授粉,但以花开后第5 d左右授粉的座果率最高。     

Chromosome location of genes controlling the content of dietary fibre and arabinoxylans in rye

Differences in fruit-set success reputed to exist between Heveabrasiliensis genetic clones were verified by an analysis of breeding recordsfor the clones PB 5/51, RRIM 600 and PR 107. Although the bestfruit-set success was obtained with PB 5/51 following artificial (hand)pollination, this clonal trait was not reflected in terms of greater numbersof pollen tubes developing it the styles of hand-pollinated PB 5/51 femaleflowers. It was observed, however, that more pollen tubes reached theovules in PB 5/51 than in RRIM 600 or PR 107. Significantly, PB 5/51female flowers required fewer pollen tubes to effect penetration of all threeof its ovules. As fruit formation in Hevea is dependent on all threeovules of the flower being successfully fertilised, PB 5/51 female flowershave hence a greater propensity for successful fruit-set. In all the threeclones studied, the frequency distribution of female flowers with 0, 1, 2 or3 of the ovules penetrated by pollen tubes did not conform to binomialexpectations. Flowers with no ovule penetrated and flowers with all threeovules penetrated were greatly over-represented. One explanation for thisnon-random distribution is the existence of `receptive' female flowers thatfavour successful fertilisation whereas `non-receptive' flowers tend to remainunfertilised even when hand-pollinated.     

球花石斛人工授粉试验

试验表明球花石斛通过人工异花授粉才能结实,同株异花在开花后第3、5、10d授粉的座果率依次为43％、52％、15％,异株异花相同时间授粉的座果率依次为45％、54％、18％,两者座果率差别不大;花开后第3～10d都能人工授粉,但以花开后第5d左右授粉的座果率最高。