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Fifty-six jujube cultivars were observed for their flowering habits and fruiting characteristics at Alcalde, New Mexico. Jujube cultivars were classified as morning blooming type or afternoon blooming type. Among the 56 cultivars observed, 24 belonged to the morning type and 32 belonged to the afternoon type. Eighteen out of the 56 cultivars had their blooming type reported for the first time. The sepal splitting for morning type occurred from sunrise to 1000hr, whereas it occurred between 1300 and 1600 hr for the afternoon type. Even though their opening time differed, pollen release happened during daytime for both—morning type released pollen in the afternoon and afternoon type released pollen in the late afternoon and the next morning. Rainy and cloudy weather delayed blooming for several hours. Each flower experienced the following stages during blooming: sepal splitting, sepal flat, petal standing, petal and anther separation, petal flat and anther standing, anther flat, and stigma browning; the time and duration of each stage varied with cultivar and blooming type. Flower size varied by cultivar and helps with cultivar identification. Cultivars Li, Li-2, Redland, Qiyuexian, Xiangzao, Teapot, and Daguazao were self-pollinating/self-fruitful in New Mexico. For open pollination, fruit set varied greatly by cultivar. ‘Abbeville’ had the best fruit set each year. Most cultivars had better fruit set from open pollination than self-pollination; however, self-fruitful cultivars Li, Li-2, and Redland had better fruit set with self-pollination than open pollination in some years. Open pollination increased fruit size for all cultivars. ‘Zhongning’, ‘Abbeville’, ‘Jinsi-2’, and ‘Globe’ had high seed percentage from open-pollinated fruit, whereas ‘Lang’, ‘Don Polenski’, ‘Junzao’, and ‘Xingguang’ did not produce fully developed seed in any years but some dark brown empty seedcoat sacs. Seed development was also affected by weather and pollination conditions. Fruit blooming type, pollen release, self-pollination, self-fruitfulness, self-fertility, and seed development are all critical information for jujube breeders, researchers, extension personnel, and growers.

Vitamin C profiles of 46 jujube cultivars were assessed from 2012 to 2015, and fruit nutrient dynamics of 10 cultivars during maturation were examined from 25 Aug. to 7 Oct. 2014 at 2-week intervals at New Mexico State University’s Alcalde Sustainable Agriculture Science Center and Los Lunas Agricultural Science Center. This is the first report in the United States profiling Vitamin C in jujube cultivars. The vitamin C content of mature fruit of 45 (of 46) cultivars ranged from 225 to 530 mg/100 g fresh weight (FW) plus ‘Youzao’ having the highest content of 820 mg/100 g FW at early mature stage. In general, drying cultivars had higher vitamin C content than fresh-eating cultivars whereas ‘Jinsi’ series (multipurpose) had relatively higher vitamin C content than others (>400 mg/100 g FW). Fruit vitamin C and moisture content decreased significantly during the maturation process. The average vitamin C contents of nine cultivars at Alcalde decreased more than 40% based on FW from 25 Aug. to 7 Oct. To maximize the vitamin C benefit, the ideal stage to consume fresh-eating cultivars is the creamy stage. Titratable acidity and soluble solids increased significantly during maturation. In mature jujubes, the titratable acidity and soluble solids ranged between 0.27% to 0.46% and 27.2% to 33.7%, respectively. Glucose, fructose, and sucrose content also rose significantly during ripening. Mature fruits contained 31–82 mg/g FW glucose, 32–101 mg/g FW fructose, and 53–159 mg/g FW sucrose among the cultivars tested. Based on sucrose contents, cultivars can be divided into two groups, “high-sucrose” (more sucrose than glucose or fructose) and “low-sucrose” (less sucrose than glucose or fructose). ‘Dagua’, ‘Honeyjar’, ‘Lang’, ‘Li’, ‘Maya’, ‘Sugarcane’, and ‘Sherwood’ belong to the “high-sucrose” group. Total phenolic content and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-reducing capacity in fruit decreased during maturation, and the total phenolic content of mature jujube was 12–16 mg gallic acid equivalent (GAE)/g dry weight (DW). For mature fruit, ‘Li’ and ‘Li-2’ had the highest DPPH-scavenging efficiency whereas ‘Sugarcane’, ‘So’, and ‘Lang’ had the lowest at Alcalde, NM.