Evaluation of Morphological Characteristics and Yield of Introduced Chinese & French Grapes Cultivars in Kenya

Abstract

Consumption of table and wine grapes (Vitis vinifera) in Kenya has increased in the recent past due to increase in the number of urban residents and expatriate communities with higher disposable income. Grapes are a good source of nutritious fruits as well as income for farmers. Grape production in Kenya is low and the country imports approximately 4,000 metric tons of wine every year. The objective of the study was to evaluate the morphological and quality characteristics of eight grape cultivars under greenhouse conditions. Three Chinese table grape cultivars (Jingyan, Jingxiangyu and Jingcui) and two Chinese wine grape cultivars (Beihong and Beifeng) as well as three French hybrid wine grape cultivars (Chenin Blanc, Sauvignon Blanc and Cabernet Sauvignon) were evaluated for fruit morphology (berries and bunches) and quality characteristics (Total Soluble Solids, Titratable Acidity, pH and sensory parameters) in 2018/2019 season using International Organization for Vine and Wine descriptors and Economic Co-operation and Development procedure for fruit and vegetables. All vines within the row were planted at a spacing of 0.9 m and 1.6 m between the rows in a completely randomized design with three vines per replication and four replications for each cultivar. Collected data were subjected to analysis of variance using SPSS to assess mean differences Pearson correlation coefficient among the cultivars. The grapes cultivars varied significantly with respect to morphological characteristics. Jingxianyu and Jingcui took the least number of days to budburst after pruning thus being classified as early bearing cultivars. Chenin Blanc and Cabernet Sauvignon recorded the highest height with respect to shoot length after 12 consecutive weeks from budburst thus being classified as vigorous cultivars. All the grape cultivars produced berries for analysis except Jingcui and Cabernet Sauvignon. Jingyan and Jingxiangyu had significantly bigger berries and higher bunch weight than all the other cultivars. The Total Soluble Solids (TSS) of the grape cultivars ranged from 16.3 to 25.2, with Sauvignon Blanc having the highest and Beihong having the least TSS. The TTA of the grape cultivars ranged from 6.32 – 25.7 g/L, with Beihong recording the highest and Jingxiangyu the least. The grapes cultivars had pH range of 3.07 to 3.55. Sensory data showed that Jingyan and Jingxiangyu were the most preferred cultivars, while Beifeng and Beihong were the least preferred. Jingxiangyu had the highest berry weight (7.64g) and highest cluster weight (440.8g) while Beifeng had the highest yield per vine (778g) translating to 5.7 Tonnes per hectare in a single season. The TTA of Sauvignon Blanc and Chenin Blanc was ideal for making stable wine while that of Beihong and Beifeng would need to be adjusted to be below 12.0g/L. Therefore, the six grape cultivars have potential for commercialization in Kenya under greenhouse conditions. The cultivars that were ideal for dessert (table use/fresh consumption) were Jingyan and Jingxiangyu. The cultivars that were ideal for processing into wine were Jingxiangyu, Jingyan, Sauvignon Blanc and Chenin Blanc. Productivity of all the varieties was not affected by disease and pest since only powdery mildew affected the vines and it was controlled by spraying Wetsulf fungicide therefore making production of grapes in a greenhouse cost-effective. Therefore, the recommendation from this study is to conduct further studies involving greenhouse production in multi-location sites to evaluate the economic viability of growing grapes in the greenhouse.