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The efficiency and responsiveness agronomic to the main macronutrients is becoming increasingly important due to the risk of supply, since it is a finite resource. In addition, excess fertilizer decreases the quality of water and air. Thus, the objective of this work was to assess the corn hybrids in terms of their efficiency and responsiveness to nitrogen (N), phosphorus (P) and potassium (K), and identify the ones most suitable for fresh consumption, according to the product type and technological level to be adopted by the farmer. The randomized complete block design in a 10 × 3 (hybrids and doses) factorial scheme was adopted for the experiment, with three replications, for two season crops (2013/14 and 2014/15). Ten hybrids (2B512PW, 2B587PW, 2B707PW, 30F35HR, 30F53YH, AG1051, BRS1055, BM3061, P3646H e P3862YH) were used in isolation under low availability (without application) and partial, of N, P and K, in an isolated manner, also evaluated under the recommended dose, aiming at fresh consumption. The most efficient and responsive hybrid must first be identified in isolation, based on the availability it is subjected to and later, by its sale, focused on fresh consumption. The hybrids indicated for low availability (low technological level) were BRS1055 and 30F53YH, with respect to responsiveness or agronomic efficiency, the hybrid P3862YH was the one that presented the best performance and indicated for technological levels of medium to high, considering the classification obtained for the nitrogen, phosphorus, and potassium for production vegetable corn.

The objective of this work was to estimate and compare phenotypic and genetic parameters after three cycles of intrapopulation recurrent selection for fresh corn grown under three nutrient availability conditions. Three experiments derived from the same population (MV-003) were conducted to assess the ability of progenies to absorb nutrients, one under adequate fertilization (control; MV-006), one under low nitrogen availability (N; MV-006N), and one under low phosphorus availability (P; MV-006P). The experiments were carried out in randomized blocks, with 64 half-sib progenies and three replications for each nutritional condition. Chlorophyll index, plant height, ear insertion, ear diameter, ear length, unhusked ear yield, and marketable husked ear were evaluated. The populations showed variability for the three nutrient availability conditions. The variability reduced after only three selection cycles; thus, evaluating a higher number of half-sib progenies, above 64, under low N and P availability is indicated. The rates used to identify the most efficient progenies in breeding programs should be close to the appropriate one, with a slow reduction after the selection cycles. The variability will be thus maintained, with a greater possibility of identifying more promising progenies. In addition, the frequency of favorable alleles increases more gradually and effectively. The N and P rate of 60 kg ha-1 is not indicated as a critical level for the initial phase of the program.

The present study aimed to evaluate the influence of fertilization formulated at planting and doses of nitrogen in topdressing on the yield components of second-crop corn. The experiment was conducted between March and June 2018 on the farm of the State University of Goiás, University Unit of Ipameri-GO. The randomized block design, arranged in a 3 x 5 factorial scheme with four replications, was used. Three fertilizer formulations at planting (06-22-12; 08-20-15 and 06-22-12 + 2% organic carbon) and five doses of N (0, 50, 100, 150 and 200 kg ha-1) in topdressing were evaluated. Leaf nitrogen content, fresh and dry mass of leaves, plant height, stem diameter, first ear insertion height, length and diameter of ears, 1000-grain weight, the mass of plants per hectare, extraction of nitrogen, and grain yield were assessed. Given the results, NPK formulated fertilizers can be used indifferently to grow second-crop corn. Nitrogen doses in topdressing have satisfactory results up to the estimated rate of 135 kg ha-1 for the cultivation of second-crop corn.

The aim of this investigative study was to identify and categorize new bean cultivars regarding their efficiency and responsiveness to nitrogen, phosphorus, and potassium, both individually and simultaneously, as well as to stipulate the cultivars that would suit each niche market based on this classification. Three experiments were conducted in the field separated by nutrients adopting the randomized block design in a factorial scheme (11 x 4) of 11 cultivars in four doses with three replications. Grain yield was the variable investigated and the means were the basis for the classification separated by in four availabilities: low, partial, adequate dose, and nutritional excess. Genetic variability was observed among the bean cultivars for efficiency and responsiveness (agronomic efficiency) to nitrogen, phosphorus, and potassium. The following cultivars: BRS Agreste, BRS Estilo, BRS Notável, and Pérola revealed the greatest values of efficiency and responsive ratings for nitrogen, phosphorus, and potassium, with indications for low and high technological levels. On the contrary, the cultivars BRS Ametista and BRS Sublime based on the efficiency and non-responsive classification showed a low ability to acquire or utilize the nutrients for grain formation. The BRS Pontal cultivar for all three nutrients displayed a high degree of efficiency with a value exceeding the average under different conditions of stress, suggesting that a more rustic cultivar best suits the market niche of small farmers.