Effect of Photoperiod after Bolting on the Expression of Gynomonoecy in Spinacia oleracea L.

Abstract

To shorten the breeding cycle in spinach, the effect of photoperiod after bolting on the expression of gynomonoecy was investigated by employing selfed-progeny of a gynomonoecious spinach plant. Seedlings were induced to bolt by an initial exposure to 16-h photoperiod under 140 µmol·m −2 ·s −1 PPFD and 20°C in a growth chamber for 3 weeks after sowing. When transferred to an 8-h photoperiod of the same PPFD, flower stalk elongation and flowering were severely inhibited; the frequency of gynomonoecious plants decreased to about a half of those under 12-and 16-h photoperiods. Under the short-day treatment, a few nodes with hermaphroditic flowers developed; the frequency of hermaphroditic flowers on gynomonoecious plants was 30, 39, and 63% under 8-, 12-, and 16-h photoperiod, respectively. Even when the light intensity under the 8-h photoperiod was doubled, the flower stalks elongated little, while 46% of the plants did not flower. When 8-h photoperiod under 280 µmol·m −2 ·s −1 PPFD was extended to 16-h, by using an incandescent lamp with an intensity of 10 µmol·m −2 ·s −1 PPFD, the seedlings produced flower stalks that were longer than those grown under 16-h photoperiod and 140 µmol·m −2 ·s −1 PPFD, and all plants flowered. There was no difference in the frequency of gynomonoecious plants and hermaphroditic flowers in both 16-h photoperiodic regimes. Extending the photoperiod to 24-h (constant light) from 8-h photoperiod at 280 µmol·m −2 ·s −1 with incandescent lights promoted flower stalk elongation more than did that by extending it to 16-h. However, the frequency of hermaphroditic flowers was almost the same in both the 16-and 24-h photoperiodic regimes. Thus, the expression of gynomonoecy after bolting in spinach was inhibited strongly under a short photoperiod and was promoted significantly by extending the photoperiod to 16-h, but extending the photoperiod to 24-h had no further effect. Therefore, it is important to extend the photoperiod to around 16-h for an efficient production of self-fertilized seeds in gynomonoecious spinach plants during the season with short photoperiods.

Effect of transplanting dates on growth, yield and quality of broad leaf mustard (Brassica juncea L. var. rugosa) varieties at Rampur, Chitwan, Nepal

“…Late sown crop encountered high temperature stress which causes a great reduction in yield (Godara et al, 2018). Furthermore, it has been reported that delaying sowing until October results in lower leaf yields since plants are subjected to long days and high temperatures exceeding 25ºC, which cause bolting and lower productivity (Changoo et al, 2001;Hata et al, 2006). Within the same location, different sowing dates provide variable environmental conditions for the growth and development of crop and yield stability as it depends on the onset of rainfall, temperature and humidity of the region (Alam et al, 2015).…”

EFFECT OF SOWING DATE AND FOLIAR SPRAY OF LUPINE SEED EXTRACT ON FOLIAGE YIELD, CHEMICAL COMPOSITION, SEED YIELD AND SEED QUALITY OF SPINACH (Spinacia oleracea L.) AS WELL AS ASSOCIATED WEEDS

“…This might be due to the longer time available for the early sown crop to utilize available growth resources (light, nutrients, moisture etc) to produce and partition more assimilates for better vegetative growth (Table 3), and this led to the production of higher seed yield and its components than the late sown plants in both seasons. In this respect, Changhoo et al (2001) and Hata et al (2006) found that a longer photoperiod during transplant production enhances floral development and increases bolting percentage. On the other hand, high temperature during the blooming stage (Table 1) of later planting may be reducing seed yield by causing floret abortion.…”

“…High NO3contents in spinach were found with low light intensities, low soil-moisture contents, high temperatures, amount of N added and the amount of N available in the soil (Breimer, 1981). Long days especially coupled with higher temperatures above 25 ºC cause the plant to bolt and flower, which is detrimental to production of spinach crop (Changhoo et al, 2001;Hata et al, 2006).…”

Flexibility of resource allocation in a hermaphroditic‐gynomonoecious herb through deployment of female and male resources in perfect flowers

“…While fl oral sex ratio is stable in some gynomonoecious species ( Bertin and Kerwin, 1998 ;Sun et al, 2006 ;Bertin et al, 2010 ), the expression of gynomonoecy is sometimes aff ected by environmental factors ( Folke and Delph, 1997 ;Hata et al, 2006 ). For example, in Solidago altissima a higher ratio of perfect-to-female fl owers was induced by the gall fl y herbivory in the low-but not high-nutrient treatments ( Wise et al, 2008 ).…”