Abstract
ABSTRACT There is little information on how different spatial arrangements affect modern maize hybrids under irrigation in the maize second growing season in Brazil. The objectives of this study were to evaluate the performance of maize genotypes with different canopy architecture as a function of different spatial arrangements in the Southeast Brazil. Two maize hybrids with semi-erect (DKB 390) and erect (DKB 230) leaves were cultivated during the second season and evaluated for different plant densities (4, 7 and 10 × 104 plants?ha?1) and row spacings (0.25, 0.50 and 1.00 m), under irrigation in a tropical environment. The increase in plant density increased plant height and ear insertion height, but reduced stalk diameter. The absorbed photosynthetically active radiation and the leaf area index also increased in higher plant densities, with a reduction of the SPAD index. The increase in plant density enhanced grain yield, however, there was no difference of yield between different row spacings. The hybrid DKB 230 (upright leaves) showed greater yield potential compared to DKB 390 (semi-upright leaves). The critical leaf area index was 5.2 and 4.3 for the hybrids DKB 230 and DKB 390, respectively. The estimated plant density that provides the maximum yield are 9.7 × 104 and 8.8 × 104 plants?ha?1 for the hybrids DKB 230 and DKB 390, respectively.
Highlights
Maize is one of the most cultivated cereals in the world, which produced an average of 1.15 billion tons per year in the last three seasons, and Brazil is the third largest producer in the world, after the United States and China
Maize is among the main agricultural commodities produced in Brazil, only in the 2019/2020 growing season an area of 18.5 million hectares was cultivated with this crop, of this total, 74% comes from the second season (CONAB 2021)
At the V13 stage, the stalk differed between row spacing (Table 1), in which RS25 and RS50 did not differ from each other (28.7 and 28.8 mm, respectively) and had a larger diameter than plants from RS100 (27.5 mm) (Fig. 2a)
Summary
Maize is one of the most cultivated cereals in the world, which produced an average of 1.15 billion tons per year in the last three seasons, and Brazil is the third largest producer in the world, after the United States and China. On average from 2015/2016 to 2017/2018 growing seasons, 81.5 million tons per year (CONAB 2021), equivalent to 7.1% of the world production (FAO 2020). Maize cultivated in the second cropping is usually sown between January and April, after soybean or dry beans Cultivation in this period of the year subjects plants to different conditions of solar radiation, photoperiod, temperature and water availability when compared to maize cultivated in the main season. This is not always considered when positioning the recommended plant spatial arrangements for the cultivars, that is, plant density and row spacing
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