Figure 5.

Relationship between climatic variables and average russeting (rating score) determined for the cumulative period of fruit maturity at ten locations in Kenya. The ten locations were: Garissa (1), Chepsigot (2), Malindi (3), Mumbuni (4), Yeemulwa (5), Kaiti (6), Kasafari (7), Kambirwa (8), Thika (9), and Machakos (10) situated at different altitudes. (a) The climatic variables include: rainfall amount (b), days with rainfall (c), relative humidity (d), minimum, maximum, and mean daily temperatures (e, f, and g, respectively). Cold nights (h) correspond to the number of days when the minimum temperature fell below the base temperature of 16 °C. Heat sum (i) was calculated based on a base temperature of 16 °C. Russeting was quantified using a five-score rating scheme: score 0: 0% of the fruit surface area russeted; score 1: 1–10% russeted area; score 2: 11–25% russeted area; score 3: 26–50% russeted area; and score 4: 51–100% russeted area. Data points represent means of 210 fruit per site.