No abstract

No abstract

We studied the effects of varying light quality on the flowering, photosynthetic rate and fruit yield of everbearing strawberry plants (Fragaria×ananassa Duch. 'HS138'), which are long-day plants, to increase the efficiency of fruit production in plant factories. The plants were grown under continuous lighting using three types of blue and red LEDs (blue light peak wavelength: 405, 450, and 470 nm; red light peak wavelength: 630, 660, and 685 nm) during the nursery period. All blue light from the various peak LED types promoted more flowering compared with red light (630 and 660 nm except for 685 nm). The longer wavelength among the red light range positively correlated with earlier flowering, whereas the number of days to anthesis did not significantly differ among blue LED treatment wavelengths, irrespective of peak wavelength. The result of a similar experiment using the perpetual flowering Fragaria vesca accession Hawaii-4 representing a model strawberry species showed almost the same pattern of flowering response to light quality. These results suggest that long-day strawberry plants show similar flowering response to light quality. The photosynthetic rate under red light (660 nm) was higher than that under blue light (450 nm). However, the plants grown under red light showed lower photosynthetic capacity than those grown under blue light. Although the light color used to grow the seedlings showed no difference in the daily fruit production, blue light irradiation during the nursery period hastened harvesting because of the advance in flowering.

To obtain basic information about flower colour sports in azalea breeding, the petals of Rhododendron · pulchrum ÔOomurasakiÕ and its red flower sport were compared in terms of pigment constitution, expression of eight genes related to flavonoid synthesis and sequences of the flavonoid 3¢,5¢-hydroxylase (F3¢5¢H) gene, which is a key gene that synthesizes the pigments of the delphinidin series. According to the HPLC analysis, ÔOomurasakiÕ contained anthocyanidins from both the cyanidin and delphinidin series, whereas the red flower sport contained only pigments from the cyanidin series. Real-time PCR analysis showed that F3¢5¢H transcript levels in the red flower sport were 0.14-fold those of ÔOomurasakiÕ. Compared with the amino acid sequences of F3¢5¢H1-A of ÔOomurasakiÕ, both F3¢5¢H1-B and F3¢5¢H1-C sequences of the red flower sport were changed by only one amino acid. These results suggested that low transcript levels of the F3¢5¢H gene caused no accumulation of delphinidin series pigments in flower colour change between ÔOomurasakiÕ and its red flower sport.

Inter-subgeneric hybrids were successfully obtained in reciprocal cross combinations between evergreen azaleas (Rhododendron nakaharae and its hybrids) and fragrant deciduous azaleas (R. arborescens and R. viscosum) for the purpose of fragrant evergreen azalea breeding. Nuclear and organelle DNA of these hybrids was investigated using PCR-RFLP markers. Viable hybrid seedlings have nuclear ribosomal DNA (nrDNA) inherited biparentally, mitochondrial DNA (mtDNA) from the seed parent, and chloroplast DNA (cpDNA) from the deciduous azalea, regardless of cross combination. These results suggest that the chloroplast genome from deciduous azaleas and the nuclear genome from evergreen azaleas are compatible in viable hybrid progenies.