Prediction of genetic gains in sweet potato genotypes by polycross

Sweet potato crops present a wide genetic diversity, but genetic parameters of populations should be estimated in breeding programs, mainly when the selection is focused on multiple traits. Thus, the objective of this study was to estimate genetic parameters and select clones via a selection index in a sweet potato population obtained from uncontrolled crosses. The experiment was carried out in Ilha Solteira, Sao Paulo, Brazil, from June to November 2020, to evaluate 144 clones and three controls, totaling 147 treatments. A randomized block design was used, with two replications and three plants per plot. The data were analyzed through mixed modeling (REML/BLUP), and the selection index proposed by Mulamba & Mock was applied using a selection pressure of 17.3% for the selection of superior clones. The direct selection enabled a higher prediction of gains for each trait, but the joint analysis maximized the selection gains for all traits of interest. Clones 38, 63, 79, 77, and 5 are recommended, among the selected clones, for further stages of sweet potato breeding focused on improving traits for production and table consumption.   Keywords: Genetic parameters, Genetic variability, Ipomoea batatas (L.) Lam, Selection gain, Selection indexSweet potato crops present a wide genetic diversity, but genetic parameters of populations should be estimated in breeding programs, mainly when the selection is focused on multiple traits. Thus, the objective of this study was to estimate genetic parameters and select clones via a selection index in a sweet potato population obtained from uncontrolled crosses. The experiment was carried out in Ilha Solteira, Sao Paulo, Brazil, from June to November 2020, to evaluate 144 clones and three controls, totaling 147 treatments. A randomized block design was used, with two replications and three plants per plot. The data were analyzed through mixed modeling (REML/BLUP), and the selection index proposed by Mulamba & Mock was applied using a selection pressure of 17.3% for the selection of superior clones. The direct selection enabled a higher prediction of gains for each trait, but the joint analysis maximized the selection gains for all traits of interest. Clones 38, 63, 79, 77, and 5 are recommended, among the selected clones, for further stages of sweet potato breeding focused on improving traits for production and table consumption.   Palavras-chave: Ipomoea batatas (L.) Lam, Variabilidade genética, Índice de seleção, Parâmetros genéticos, Ganho com seleçã

Performance of crispy lettuce cultivars in different soil covers

The lettuce cropping is an important segment of the national agriculture, with strong economic expression. However, climatic factors such as high temperature and humidity can affect this vegetable cultivation. These environmental conditions are common in various Brazilian regions, so the growers should adopt crop management systems, as soil covers, to minimize the environmental effect and obtain higher returns. Thus, the aim of this study was to evaluate the influence of different soil covers on the agronomic performance of crispy lettuce cultivars. The study was conducted at UNESP, Registro Campus, Brazil, from August to October, 2013. The experiment was carried out in a randomized blocks design, arranged in a 4x4 factorial, with three repetitions. The treatments consisted of the factors soil covers (black mulching, silver mulching, white mulching and control) and cultivars (Inaiá, Milena, Vanda and Vera). The experimental unit consisted of fifteen plants, with the useful area composed of nine central plants. At harvest, the following characteristics were evaluated: plant height, head diameter, fresh mass, number of leaves, leaf width, leaf height, stem diameter, heart diameter, heart height, dry mass, yield and nitrate content. Among the studied covers, white mulching showed the best results for the main productive characteristics and can be used as soil cover in the cultivation of Vera, Vanda and Inaiá culivars.The lettuce cropping is an important segment of the national agriculture, with strong economic expression. However, climatic factors such as high temperature and humidity can affect this vegetable cultivation. These environmental conditions are common in various Brazilian regions, so the growers should adopt crop management systems, as soil covers, to minimize the environmental effect and obtain higher returns. Thus, the aim of this study was to evaluate the influence of different soil covers on the agronomic performance of crispy lettuce cultivars. The study was conducted at UNESP, Registro Campus, Brazil, from August to October, 2013. The experiment was carried out in a randomized blocks design, arranged in a 4x4 factorial, with three repetitions. The treatments consisted of the factors soil covers (black mulching, silver mulching, white mulching and control) and cultivars (Inaiá, Milena, Vanda and Vera). The experimental unit consisted of fifteen plants, with the useful area composed of nine central plants. At harvest, the following characteristics were evaluated: plant height, head diameter, fresh mass, number of leaves, leaf width, leaf height, stem diameter, heart diameter, heart height, dry mass, yield and nitrate content. Among the studied covers, white mulching showed the best results for the main productive characteristics and can be used as soil cover in the cultivation of Vera, Vanda and Inaiá culivars

TELAS DE SOMBREAMENTO NO DESEMPENHO DE CULTIVARES DE ALFACE

Resumo: A crescente demanda por hortaliças com qualidade e periodicidade faz com que agricultores procurem por meios que possibilitam essa produção. Desta forma o presente trabalho teve como objetivo avaliar o desempenho de cinco cultivares de alface quando submetidas a quatro tipos de cobertura. O experimento foi conduzido entre 16 de fevereiro de 2012 e 10 de maio de 2012, sendo a primeira etapa na área experimental do Setor de Olericultura da Universidade Estadual Paulista Campus Experimental de Registro, em Registro-SP e a segunda etapa no sitio Colônia Jurumirim, em Sete Barras-SP. O delineamento experimental utilizado foi o de blocos ao acaso em parcelas subdivididas, com vinte tratamentos (Cultivares: Angelina, Vera, Elisa, Regiane e Lavinia e coberturas Sombrite 50%, Aluminet, Cromatinet e Campo Aberto) e três repetições. As características avaliadas foram: massa fresca, massa seca, diâmetro da cabeça, número de folhas por cabeça e produtividade por área. Dentre os ambientes, o cultivo em campo aberto apresentou maior produtividade. As cultivares Regiane, seguido de Angelina apresentaram os maiores valores para produtividade

Doses de potássio na produção da alface

A utilização de fertilizantes minerais em alface é uma prática agrícola que traz resultados satisfatórios, porém, é necessário saber qual dose ótima de acordo com cada tipo de solo. Desta forma, objetivou com este trabalho avaliar a influência de doses de potássio (K) sobre o crescimento e produção de alface 'Vera', em um solo contendo baixos teores de K (0,3  mmolc dm-3). O experimento foi realizado de 3 de setembro de 2011 a 4 de janeiro, de 2012, em blocos casualizados com seis tratamentos (0, 50, 100, 150, 200 e 250 kg ha-1 de K2O) e quatro repetições. A alface foi colhida 45 dias após o transplante das mudas. Foram verificados efeitos significativos na massa fresca e seca da parte aérea, teor de K no solo e acúmulo de K na planta, os quais foram maximizados com as doses de 180, 153, 250 e 250 kg ha-1 de K2O, respectivamente. Não houve diferença significativa para o teor foliar de K nas doses de K2O avaliadas. Em Argissolo Vermelho Amarelo distrocoeso, com baixa disponibilidade de potássio, a alface responde positivamente a adubação potássica, sendo necessários 180 kg ha-1 de K2O