Benti Tesfaye, Debela Adugna, Bekele Yetenayet, Suleman Sultan
Department of Horticulture College of Agriculture in Mizan Tepi University Southwest Ethiopia, Ethiopia.
Ethiopia Coffee and Tea Authority, Oromia, Ethiopia.
Heliyon. 2023 Feb 24;9(3):e14051. doi: 10.1016/j.heliyon.2023.e14051. eCollection 2023 Mar.
The tea plant is widely cultivated in southwest Ethiopia. But the impact of seasonal variation on monthly yield, leaf quality, and the long-term yield response potential of clones has not been studied. The objective of the study is to determine the impact of seasonal change and climate variables on the yield and leaf quality of tea plants in southwest Ethiopia. The experiment consisted of five clones and four seasons under a split-plot design and was replicated three times. The results indicated that the yield and leaf quality showed significant variation in the different seasons at P < 0.05. The highest peak yields of 12.68, 12.59, and 11.3 kg plot were recorded in May, June, and April, respectively, and the yield suddenly dropped by 5.1% in July. Then the soft banjhi increased by 5-10% in July. The yield response potential of clones is highly affected by monthly climate variation at P < 0.05. Clone BB-35 recorded the highest (18.8 kg plot) yield in June, followed by clones 11/4 (18.3) in May, 11/56 (14.7) in November, 6/8 (11.7) in December, and 12/38 (5.78 kg plot) in June. The lowest mean green leaf and a longer shoot replacement cycle were created due to a decrease in rainfall to 760 mm/month and rising temperatures above 26.35 °C in winter. The leaf phenological response of tea clones is strongly governed by the monthly temperature and suitable precipitation pattern of a season. The highlands have two harvesting seasons, i.e., a dry and a wet harvesting season. The dry harvesting season, which exists between the middle of December and March, accounts for 18.3-24.3% of the total annual yield. The wet harvesting season is subdivided further into two peak harvesting seasons. The first harvest is characterized by a short plucking round, and the highest peak yield occurs in April, May, and June, accounting for 40.22-42.2% of the total annual yield. The second wet harvesting season begins in September and ends in the middle of December, contributing to 35.5-40% of the annual yield. Seasonal variation has a direct impact on leaf quality and clone yielding potential. Clones show higher yield and shorter plucking rounds at maximum temperatures above 23.03 °C and below 26.35 °C, but temperatures above 28.34 °C and below 10.38 °C have a negative effect on leaf quality and yield. Over the last two decades, rainfall, maximum, and mean temperatures all increased by 16.09 mm y-1, 0.127 °C, and 0.0566 °C y, respectively, and the tea plant showed a strong correlation with maximum temperature (76%), whereas mean temperature (44.6%) and annual rainfall (32.8%) correlated weakly. Green leaf production is well explained by around 85.4% of the observed climate variance, with an increase of 1287.18 tonnes y, and highland tea production will exhibit a positive net benefit from expected climate change in the future.
茶树在埃塞俄比亚西南部广泛种植。但季节性变化对月产量、叶片质量以及无性系长期产量响应潜力的影响尚未得到研究。本研究的目的是确定季节变化和气候变量对埃塞俄比亚西南部茶树产量和叶片质量的影响。试验采用裂区设计，包括5个无性系和4个季节，重复3次。结果表明，在P<0.05时，产量和叶片质量在不同季节表现出显著差异。5月、6月和4月分别记录到最高峰值产量，分别为12.68、12.59和11.3千克/小区，7月产量突然下降5.1%。然后，7月软枝增加了5-10%。在P<0.05时，无性系的产量响应潜力受月气候变化的影响很大。无性系BB-35在6月产量最高（18.8千克/小区），其次是5月的11/4（18.3）、11月的11/56（14.7）、12月的6/8（11.7）和6月的12/38（5.78千克/小区）。由于冬季降雨量降至760毫米/月且气温升至26.35℃以上，导致绿叶平均产量最低且新梢更替周期延长。茶树无性系的叶片物候响应受月温度和季节适宜降水模式的强烈影响。高地有两个收获季节，即旱季收获季节和雨季收获季节。12月中旬至3月的旱季收获季节占全年总产量的18.3-24.3%。雨季收获季节进一步细分为两个峰值收获季节。第一次收获的特点是采摘轮次短，最高峰值产量出现在4月、5月和6月，占全年总产量的40.22-42.2%。第二个雨季收获季节从9月开始，到12月中旬结束，占年产量的35.5-40%。季节变化对叶片质量和无性系产量潜力有直接影响。无性系在最高温度高于23.03℃且低于26.35℃时产量较高且采摘轮次较短，但温度高于28.34℃且低于10.38℃对叶片质量和产量有负面影响。在过去二十年中，降雨量、最高温度和平均温度分别以每年16.09毫米、0.127℃和0.0566℃的速度增加，茶树与最高温度的相关性很强（76%），而与平均温度（44.6%）和年降雨量（32.8%）的相关性较弱。约85.4%的观测气候方差能很好地解释绿叶产量，产量增加了1287.18吨/年，未来高地茶叶生产将从预期的气候变化中获得正的净效益。
