Avaliação agronômica e composição química de híbridos de sorgo forrageiro em classificações climáticas diferentes.

Abstract

The objective was to determine the agronomic characterization and chemical composition among silage sorghum hybrids under rainfed conditions, planted in different climatic classifications, and through the results to point out the one that produces the best on the climatic conditions of the explored regions. The research was carried out in two different climates, in climate 1 (Bsh) semiarid and climate dry subhumid 2 (Bsh), both in the state of Piauí. Each trial consisted of 20 experimental sorghum hybrids (Sorghum bicolor (L.) Moench], and three commercial Sorghum hybrids. For agronomic evaluation, the total plant height, number of tillers per linear meter, lodging, leaf/stem ratio (FO/CO) were quantified. In ha-1, leaves, stems, panicles, dead matter (MM), green forage mass (GFM), and total dry fodder (TDF) were evaluated. In the chemical composition, the contents of dry matter (DM), crude protein (CP), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (CEL), hemicellulose (HEMIC) were determined) and lignin (LIG). For growth characteristics, there was an interaction (P <0.05) for the variables plant height, lodging and leaf/stem ratio, between the different climates and hybrids evaluated. For the variable number of tillers, there was a difference (P <0.05) only between hybrids. In climate 2 there was no difference between the hybrids (P = 0.05) only for the lodging variable. There was interaction (P <0.05), for production of dead matter and dry matter of forage between the different climates and hybrids evaluated. For leaf production there was an effect (P <0.05) only for different climates. For the chemical characteristics, there was an interaction (P <0.05) for the variables DM, OM, CP, NDF, ADF, CEL, HEMIC and LIG, between the different climates and hybrids evaluated. The 870031 hybrid had higher plant height in both climates, with an average of 239.1 ± 8.7 cm in climate 1 and 168.8 ± 8.7 cm in climate 2. Hybrids 866005, 866019 and 866033 had higher averages tillers, ranging from 11.4 ± 7.8 to 11.7 ± 7.8 tillers / linear meter. The hybrids that had the highest MVF and MSF averages in both climates were 870031, 870035, 870085 and 870095 with averages ranging from 61.5 ± 6.3 to 72.86 ± 6.3 t ha-1 of GFM and 23.3 ± 3.4 to 29.5 ± 3.4 t ha-1 of TDF. The hybrids with the highest CP mean in both climates were 866005, 866019, 866033, 866034, 866037, 866040 and 870025, with averages ranging from 8.4 ± 0.86 to 11.4 ± 0.86%. The recommended hybrids were 870031, 870095 and 1F305, as in addition to presenting high yields of green matter and dry matter, they also showed a high chemical composition mainly in PB in the two locations evaluated, showing great adaptability to different climates.