Crescimento e produtividade de melão Cantaloupe 'Acclaim' em cultivo protegido utilizando agrotêxtil

Abstract

In Rio Grande do Norte, the melon growers have been using the row cover on the roof of the plants to start flowering in order to reduce the population of insect pests that cause severe losses, rising production costs, especially with the application of defensive. Thus, it is important to know the best time to remove the row cover because, due to its use, it is assumed that there are changes in the physiological response of plants. In order to evaluate the growth and yield of the melon plants 'Acclaim' cultivated under protection agrotextile (TNT) for different periods, a trial was conducted at the Universidade Federal Rural do Semi-árido, Mossoró, Rio Grande do Norte state. The experimental design was a randomized complete block, with four replications, in a splitplot, the plots were the plant protection periods (0, 18, 21, 24, 27 and 30 days after transplanting, DAT), and splitplots, times of sampling the plants (13, 20, 27, 34, 41, 48 and 55 DAT). We evaluated the dry matter accumulation in leaves (LDMA), branches (BDMA), flowers (FDMA), fruits (FrdMA) and total (TDMA), assimilate partitioning, leaf area index (LAI), leaf weight ratio (LWR), absolute growth rate (AGR) and relative (RGR), net assimilation rate (NAR), total (PTOT) and marketable productivity (PCOM). The treatments with plant protection did not affect the TDMA which peaked at 295.12 g plant -1 at 53 DAT, with the fruits behaving like sink preferred plant, accounting for 72.25% of the dry mass accumulated. The LAI and the AGR grew by 55 and 42 DAT (1.95 and 18.518 g/plant/day), respectively, while the LWR and RGR decreased over the cycle, with peaks of 0.911 and 0.242 g/g/day, at 13 and 20 DAT, respectively. The PTOT and PCOM were not affected by periods of plant protection, with averages of 29.30 and 22.25 t ha -1, respectively, indicating that it is possible to manage the row cover in order to remove it later, that reduces costs and crop protection without significant loss in productivity.