Sl. Zhang et S. Hiratsuka, Analysis of varietal differences in self- and cross-incompatibility reactions of Japanese pears using stylar culture technique, J JPN S HOR, 68(2), 1999, pp. 373-383
Citations number
12
Categorie Soggetti
Plant Sciences
Journal title
JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE
Varietal differences of pollen tube growth among self-, cross-incompatible
and cross-compatible pollinations were investigated by semi vitro assay usi
ng detached styles in Japanese pear (Pyrus serotina Rehd. var. culta Rehd.)
cultivars.
Among the 52 self-compatible and -incompatible cultivars, the pollen tubes
grew in considerably different ways. The percentages of styles with protrud
ing pollen tubes from the basal cut end ranged from 0 to 47. Pollen tubes o
f 'Shinsetsu', Nihonyamanashi, self- compatible 'Osa-Nijisseiki', and self
-compatible strains obtained from 'Osa-Nijisseiki' grew well, and those of
'Okusankitsu', 'Yasato', 'Kikusui', 'Nijisseiki', and 'Kisui' did intermedi
ately, whereas pollen tubes of 'Shinsui', 'Chojuro', 'Kimizukawase', 'Hohsu
i','Kohsui', and 'Kohzo' grew poorly. Similar tendencies were observed when
the number of pollen tubes protruding from the basal cut end among cultiva
rs was counted. Generally, pollen tubes of cultivars derived from 'Nijissei
ki' grew better than did those of 'Kohsui' and 'Shinsui', indicating that t
he rate of pollen tube elongation of cultivars is a heritable character.
In cross-incompatible and -compatible pollination combinations, the pollen
tubes grew quite differently, depending on the parental combinations. The p
ercentages of styles with protruding pollen tubes from the cut end ranged f
rom 0 to 40 in cross-incompatible combinations, and from 26 to 97 in cross-
compatible ones.
By using excised styles shortened to 1/2 or 1/3 of the original length, the
percentage of styles with protruding pollen tubes from the cut end improve
d. The growth of self- and cross-incompatible pollen tubes became much bett
er so that the promotion patterns were classified as follows: 1) tube elong
ation becomes better as the style is shortened; 2) tube elongation becomes
better but there are no differences between 1/2 and 1/3 reduction in style
length; 3) pollen tube elongation becomes better only in the 1/3 style leng
th, and 4) no change was found. These differences indicate that the inhibit
ion of pollen tube growth occurs in different parts of the style among resp
ective cultivars.