Screening Of Low Light Tolerance Grape Cultivars Based On Analysis Of Photosynthetic Characteristics In Protected Cultivation

To understand the photosynthesis characteristics and screen low light tolerance grape cultivars for protected cultivation. Photosynthetic characteristics and chlorophyll fluorescence of 47 grape cultivars were measured and analyzed. By fitting the measurement results of photosynthesis, light compensation point(LCP), light saturation point(LSP) and other characteristic parameters of each grape cultivars were obtained. Through experimental research the following conclusions were obtained.(1)Photosynthetic characteristics and low light tolerance analysis of grape cultivars in protected cultivationGrape cultivars with low LCP showed higher net photosynthetic rate(Pn) and performed stronger photosynthetic ability than high LCP grapes under low light condition. According to the numeric value of LCP, 19 grape cultivars could be divided into three categories which showed different tolerance to low light: 1) 0~ 10 ?mol·m-2·s-1, Red Rosa, White Rosa; 2) 10 ?mol·m-2·s-1~ 30 ?mol·m-2·s-1, Kyoho, 10-1, Early Jasmine, Yatomi Rosa, Jingya; 3) 30 ?mol·m-2·s-1~ 50 ?mol·m-2·s-1, Xuwang No.4, Augusta, Zaohong Seedless, Himrod Seedless, Summer Black, Manicure Finger; 4) 50 ?mol·m-2·s-1~ 100 ?mol·m-2·s-1, Italian, Fujiminori, Centenial seedless, Jumeigui, Zuijinxiang; 5) Greater than 100 ?mol·m-2·s-1, Christmas Rose. Also, LCP showed significant positive correlation with dark respiration rate(Rd), while there was no clear correlation between LCP and chlorophyll fluorescence. LCP?Rd and Pn could be looked as the indicators to determine the low light tolerance of grapes. Low light tolerance cultivars had low LCP and Rd value, high Pn in low light. 13 grape cultivars such as Red Rosa were found had strong low light tolerance. Among which 12 grape cultivars: Red Rosa,Kyoho, 10-1, Early Jasmine, Yatomi Rosa, Jingya, Xuwang No.4, Augusta, Zaohong Seedless, Himrod Seedless, Summer Black, Manicure Finger also had strong light tolerance.(2)Screening low light tolerance grape cultivars introduced from JapanAccording to the numeric value of LCP, 28 grape cultivars could be divided into three categories which showed different tolerance to low light: 1) 0~ 10 ?mol·m-2·s-1, Shinano Smile, Unicorn, Shien, Sunny Rouge, Rich Baba, Baby Finger, Ryogyoku, Red Pot, Muscat Duke Amour; 2) 10~ 30 ?mol·m-2·s-1, Royal, Oriental Star, Late Rizamat, Minikaiji, Black Beet, Black Swan, Black Sanjiaku, High Bailey, Muscat Violet, Shyuuhyo, Kourgan Rose, Sagami; 3) 30~ 50?mol·m-2·s-1, MTC Steuben, Cannon Hall Muscat; 4) Greater than 50 ?mol·m-2·s-1, Rosaki, Seto Giants, Shine Muscat, Ichikimal, Green Summer. Choosing LCP?50?mol·m-2·s-1, LSP?1000 ?mol·m-2·s-1, Pm?10 ?mol·m-2·s-1 as the initial screening criteria, Muscat Violet, High Bailey, Black Sanjiaku, Black Beet, Red Pot, Ryogyoku, Baby Finger, Rich Baba, Sunny Rouge, Shyuuhy, Kourgan Rose, Sagami, Cannon Hall Muscat were low light tolerance grape cultivars for protected cultivation.