Screening of low light tolerance grape cultivars based on analysis of photosynthetic characteristics in protected cultivation

Abstract: 【Objective】The study was to provide the basis for screening low light tolerance grape cultivars for protected cultivation.【Methods】Forty-seven grape cultivars including 19 commonly cultivated cultivars in Shanghai and 28 cultivars newly introduced from Japan were involved in the study. Photosynthetic characteristics and chlorophyll fluorescence of 47 grape cultivars were measured and analyzed.【Results】According to the photosynthetic characteristic parameters and chlorophyll fluorescence parameters,low light capability of 47 cultivars were evaluated. Light compensation point (LCP) and dark respiration rate(Rd) was a significant positive correlation,Rd was the main factor affecting the LCP,and low light tolerance cultivars had lower Rd and higher net photosynthetic rate (P_n) under low light. According to the numeric value of LCP,47 grape cultivars could be divided into five categories which showed different tolerance to low light: 1) Extremely low light tolerance cultivars (0~ 10 μmol·m^-2·s^-1),such as‘ShinanoSmile'‘Unicorn'‘Shien'‘Red Rosa'‘White Rosa'‘Sunny Rouge'‘Rich Baba'‘Baby Finger'‘Ryogyoku'‘Red Pot' ‘Muscat Duke Amour';2) Low light tolerance cultivars(10~ 30 μmol·m^-2·s^-1),containing ‘Kyoho' ‘Royal' ‘Oriental Star' ‘10-1' ‘Late Rizamat' ‘Minikaiji' ‘Black Beet' ‘Black Swan'‘Black Sanjiaku'‘High Bailey'‘Muscat Violet'‘Early Jasmine' ‘Shyuuhyo' ‘Kourgan Rose' ‘Yatomi Rosa' ‘Sagami'‘Jingya';3) Relatively low light tolerance cultivars(30~ 50 μmol·m^-2·s^-1),such as‘Xuwang No.4' ‘Augusta' ‘Zaohong Seedless' ‘Himrod Seedless' ‘MTC Steuben'‘CannonHall Muscat'‘Summer Black'‘Manicure Finger';4) Low Light intolerant cultivars(50~ 100 μmol·m^-2·s^-1),including‘Italian'‘Rosaki'‘Seto Giants' ‘Shine Muscat'‘Fujiminori'‘Centenial Seedless' ‘Ichikimal'‘Green Summer'‘Muscat Kyoho'‘Zuijinxiang';5) Extremely low Light intolerant cultivars(Greater than 100 μmol·m^-2·s^-1),for instance,‘Christmas Rose'.【Conclusion】Pn,LCP and Rd are basic parameters for the evaluation of low light tolerance capability of grape cultivars. 36 cultivars(LCP: 0~ 50 μmol·m^-2·s^-1) including‘Shinano Smile'‘Unicorn'‘Shien'‘Red Rosa'et al. had strong low light tolerance and were suitable for forcing culture in early spring,among which 25 cutivars ‘(Kyoho'‘Summer Black'‘Yatomi Rose'‘Red Rosa'‘Himrod Seedless' ‘Jingya'‘Manicure Finger'‘Augusta'‘Muscat Violet'‘Sunny Rouge'‘Ryogyoku'‘Rich Baba'‘High Bailey'‘Red Pot'‘Baby Finger'‘Black Sanjiaku'‘10- 1'‘Black Beet'‘Zaohong Seedless' ‘Xuwang No. 4'‘Sagami'‘Kourgan Rose'‘Shyuuhyo'‘Early Jasmine'‘Cannon Hall Muscat'et al) also had stronger tolerance capability to the strong light.