PREDICTING YIELD AND TIME TO MATURITY OF MUSKMELONS FROM WEATHER AND CROP OBSERVATIONS

A Simple method to predict time from anthesis of perfect flowers to fr uit maturity (full slip) and yield is presented here for muskmelon (Cu cumis melo L.) grown in a northern climate. Developmental time for ind ividual muskmelons from anthesis to full slip could be predicted from several heat unit formulas, depending on the temperature data set used . When temperature at 7.5 cm above soil level was used, the heat unit formula resulting in the lowest coefficient of variation (cv = 6.9 %) accumulated daily average temperatures with a base temperature of 11 d egrees C and an upper threshold of 25 degrees C. With temperatures rec orded at a meteorological station located 2 km from the experimental f ield, the method showing the lowest cv (8.9%) accumulated daily maximu m temperatures with a base temperature of 15 degrees C. This latter me thod was improved by including a 60-degree-day lag for second cycle fr uit. The proportion of fruit volume at full slip of 22 fruit from the first cycle could be described by a common Richards function (R-2 = 0. 99). Although 65% of the plants produced two fruit cycles, fruit from the first cycle represented 72% of total yield in terms of number and mass. The blooming period of productive flowers lasted 34 days, each c ycle overlapping and covering an equal period of 19 days. Counting the number of developing fruit >4 cm after 225 degree days from the start of anthesis (when 90 % of the plants have at least one blooming perfe ct flower) could rapidly estimate the number of fruit that will reach maturity.