Yang Lyu1,2, Ron Porat3, Uri Yermiyahu1, Yehuda Heler1,4, Doron Holland5, Arnon Dag1. 1. Gilat Research Center, Agricultural Research Organization (ARO), Volcani Center, Gilat, Israel. 2. Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China. 3. Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion, Israel. 4. Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel. 5. Newe-Ya'ar Research Center, Agricultural Research Organization (ARO), Volcani Center, Ramat Yishay, Israel.
Abstract
BACKGROUND: Nitrogen (N) fertilization influences plant growth and yield, and may also affect fruit quality. For two consecutive seasons, we examined the effects of various N fertilization levels - 5 to 200 mg L-1 - on pomegranate fruit, aril and juice quality. Evaluations included fruit and aril weight, size and color, appearance of peel blemishes, internal black rot and nutritional composition of extracted juices. RESULTS: Nitrogen fertilization affected pomegranate fruit, aril and juice quality. The most pronounced effects were observed in trees grown under the lowest N fertilization level, which bore smaller fruit and arils, the latter with lighter color; the fruit suffered from sunburn, and the juice had lower total soluble solid, acidity and anthocyanin contents. The proportion of edible aril weight per total fruit weight gradually increased with an increase in N fertilization concentration. In contrast, N fertilization did not affect peel color, roughness or cracking incidence. Black rot incidence increased with increasing N concentration. CONCLUSIONS: Nitrogen fertilization affected pomegranate fruit, aril and juice quality, and the total number of marketable fruits per tree. The optimal N fertilization levels, which were most beneficial for achieving high-quality marketable fruit, were between 40 and 100 mg L-1 .
BACKGROUND:Nitrogen (N) fertilization influences plant growth and yield, and may also affect fruit quality. For two consecutive seasons, we examined the effects of various N fertilization levels - 5 to 200 mg L-1 - on pomegranate fruit, aril and juice quality. Evaluations included fruit and aril weight, size and color, appearance of peel blemishes, internal black rot and nutritional composition of extracted juices. RESULTS:Nitrogen fertilization affected pomegranate fruit, aril and juice quality. The most pronounced effects were observed in trees grown under the lowest N fertilization level, which bore smaller fruit and arils, the latter with lighter color; the fruit suffered from sunburn, and the juice had lower total soluble solid, acidity and anthocyanin contents. The proportion of edible aril weight per total fruit weight gradually increased with an increase in N fertilization concentration. In contrast, N fertilization did not affect peel color, roughness or cracking incidence. Black rot incidence increased with increasing N concentration. CONCLUSIONS:Nitrogen fertilization affected pomegranate fruit, aril and juice quality, and the total number of marketable fruits per tree. The optimal N fertilization levels, which were most beneficial for achieving high-quality marketable fruit, were between 40 and 100 mg L-1 .