Effects Of Small Arch Shed On Different Varieties Of Spring Sowing Garlic In The Formation Of Single-clove Garlic

The formation of single-clove garlic is due to garlic in vegetative prophase without vernalization stage, unable to differentiate form flower buds and axillary bulblet, thus forming bulbs without split. The single-clove garlic has higher nutritive value and market value, so the research of the factors on affecting the formation of single-clove garlic has important significance. Previous experiments studied sowing dates, cultivars, temperature and other factors on the formation of single-clove garlic, but small arch shed covering on the formation of single-clove garlic is rarely reported. In this experiment, the effects of small arch shed covering on the formation of single-clove garlic of spring sowing garlic were studied. Two dates of small arch shed covering were designed in the experiment(10 d, 20 d). Single-layer film covering was the control group. Five varieties were chosed, including “Ledu zi” “Japan garlic” “Japan rocambole” “Xinjiang zi No.2” “Hebei-baigou”. The overarching goal of this study was to provide a reference to gain high yield and good quality of single-clove garlic.The main results were as follows:1. The results showed that the plant height, the false stem length, the false stem diameter, leaves width and length of the five varieties of garlic were significantly increased by small arch shed covering for 10 days, while the latter temperature exceeded the optimum temperature of garlic by small arch shed covering for 20 days, This is harmful to the growth of garlic. The growth of “Ledu zi” is the largest, The growth of “Hebei-baigou” is second and the growth of “Japan rocambole” is minimum under the same treatment.2. The content of soluble sugar, soluble protein, vitamin C and Allicin in leaves were highest in small arch shed covering for 10 days. While the effects of small arch shed covering for 20 days was not significant. The content of soluble sugar, soluble protein, vitamin C and Allicin in leaves were higher than other four species under the same treatment, but soluble sugar content below the other four species. In addition, Treated by small arch shed covering for 10 days the content of MDA was decreased in leaves, this has close relation to the increase of the content of SOD, POD and CAT in leaves; Treated by small arch shed covering for 20 days the content of MDA was increased in leaves, this has close relation to arch canopy temperature is exceeded the optimum temperature of garlic.3. Treated by small arch shed covering for 10 days, the content of pigment, net photosynthetic rate(Pn) and stomatal conductance were higher than other treatment and control group. But the effect of CO2 concentration on the intercellular space was not obvious. Covering with small arch shed for 10 days, net photosynthetic rate(Pn) of “Ledu zi” “Japan garlic” “Japan rocambole” “Xinjiang zi No.2” “Hebei-baigou” were respectively increased 16.9%, 21.1%, 11.3%, 15.9% and 13.2%,than that in CK. The effects of small arch shed covering for 20 days on the content of pigment and net photosynthetic rate in the leaves of garlic was not obvious4. The single-clove rate and single head weight were at first in small arch shed covering for 10 days. Small arch shed for 10 d appropriately raise the temperature, to avoid the occurrence of garlic vernalization, increase the rate of single-clove garlic. At the same time, it also promote the growth of garlic bulbs. With small arch shed covering for 10 d or 20 d or 0 d, the single rate of Hebeibaigou is 94.6%, 85.2%, 80.1%, respectively, which was higher than other varieties. The single clove weight of Hebei-baigou is 6.8 g, 5.9 g, 5.5 g by small arch shed covering for 10 d or 20 d or 0 d, which was lower than Leduzi. The single head weight of Leduzi is more than 8 g but the single-clove rate of it is less than 30%, so it isn't suitable for production of single-clove garlic in spring.5. Small arch shed covering could increase the content of allicin, vitamin C, soluble protein and soluble sugar in single-clove garlic bulds, and the treatment of small arch shed covering 10 days has the best effect. Covering with small arch shed for 10 days, the contents of allicin, vitamin C, soluble protein and soluble sugar in single-clove garlic bulds of Hebei-baigou were increased 12.6%, 13.2%, 4.4%, 6.9%, respectively. But the content of allicin, vitamin C, soluble protein and soluble sugar in single-clove garlic bulds of other varieties was slightly improved.