Abstract The objective of this study was to select a population of sugarcane clones to develop energy cane cultivars. The genotypic means of 124 clones were estimated for the yield-related traits: mean number of stalks per plant (NS), mean stalk weight (MSW), fiber content (FIB), lignin content (LIG), and sucrose content in cane juice (SPC). From these data, the traits tons of cane per hectare (TCH), tons of fiber per hectare (TFH) and tons of lignin per hectare (TLH) were estimated. The clone effects were statistically significant (p <0.01) for all traits except TLH and LIG. Clone UFV09251 had the highest genotypic values for TFH and TCH. Clone UFV09270 had a high fiber content (15.04%) and clone UFV09225 a high sucrose content (14.05%). The correlation between TFH and TCH was high (0.89). Clone UFV09251 is highly promising as energy cane cultivar, for producing most TCH and FIB.

Abstract The objective of this study was to identify superior parents for crosses and the best families to breed new clones of energy cane. The best-performing parents were RB867515, RB93509, KRAKATAU, IM76-228, IM76-229, and US85-1008. The heritability and accuracy values for the traits tons of cane per hectare, fiber, and sucrose content indicate high correlation between the predicted genotypic means and observed values, enabling efficient selection of the best cane energy families. The extensive genetic variation detected and the presence of promising seedlings in the selected segregating population indicate the possibility of using new crosses in some clones and even in future commercial plantings. It was possible to identify the best parents involved in the evaluated crosses, and to select, in the best families, seedlings with a high fiber and good sucrose content, seedlings with high fiber and low sugar content, as well as seedlings with the same fiber and sucrose contents as the current cultivars.

O objetivo dessa pesquisa foi avaliar a diversidade genética e a relação de parentesco entre 50 genótipos de canade- açúcar, além de identificar genitores potenciais para a obtenção de cultivares cana energia. A análise de diversidade foi realizada a partir da avaliação de caracteres morfológicos e agronômicos. O coeficiente de parentesco foi obtido a partir das informações de pedigree. De acordo com as análises realizadas os genótipos foram separados em dois grupos. O grupo G1 foi formado por 13 genótipos descendentes das espécies Saccharum spontaneum e Saccharum robustum. Os outros 37 genótipos descendem de retrocruzamentos com Saccharum officinarum e foram alocados no grupo G2. Os genótipos apresentaram baixos valores de similaridade genética e de coeficiente de parentesco, indicando ampla variabilidade genética na população. A condução de cruzamentos envolvendo genótipos do grupo G1, principalmente aqueles com teor de fibra acima de 17% (IJ76-293, 57NG12, IN84-82, IN84-88, IM76-228 e UM69/001), com os genótipos do grupo G2, que apresentam elevada produtividade de colmos (RB92579, RB83102, RB047232, RB867515, RB971723, RB937570, RB011941, RB75126, MEX68- 200, Co62175 e CP691052), devem ser explorados com a finalidade de desenvolver cultivares cana energia. As análises de diversidade e do coeficiente de parentesco permitiram a identificação de dois grupos heteróticos. Além disso, foi possível identificar nos dois grupos genitores potenciais para a obtenção de cultivares cana energia. A utilização das distâncias genéticas com base em dados morfo-agronômicos e do pedigree devem ser usadas de forma complementar, visando agregar maior conhecimento na escolha dos melhores genitores.

The aim of this study was to evaluate the genetic diversity and coefficient of kinship in 50 sugarcane genotypes, in addition to identifying potential parents for obtaining cultivars of energy cane. Diversity analysis was carried out based on the evaluation of morphological and agronomical characteristics. The coefficient of kinship was obtained from information on pedigree. According to analyses carried out, genotypes were separated into two groups. Group G1 consisted of 13 genotypes from the species Saccharum spontaneum and Saccharum robustum. The other 37 genotypes were from back-crosses with Saccharum officinarum, and were allocated to group G2. The genotypes displayed low values for genetic similarity and coefficient of kinship, indicating broad genetic variability in the population. Carrying out crosses involving genotypes from group G1, especially those with a fibre content of over 17% (IJ76-293, 57NG12, IN84-82, IN84-88, IM76-228 and UM69/001), with genotypes from group G2 which have high stalk yield (RB92579, RB83102, RB047232, RB867515, RB971723, RB937570, RB011941, RB75126, MEX68-200, Co62175 and CP691052), should be explored, with the aim of developing energy cane cultivars. Analyses of diversity and of the coefficient of kinship made it possible to identify two heterotic groups. Moreover, it was possible to identify two potential parent groups for obtaining energy cane cultivars. Genetic distances which are based on both morpho-agronomical data and on pedigree, should be used in a complementary way, with a view to having more information when choosing the best parents.

Local maize (Zea mays L.) varieties are cultivated by small-scale farmers in western Santa Catarina (SC) State, in southern Brazil. These small areas frequently present many problems related to biotic and non-biotic stresses, which have limited the economic output and income of the farmers. Production from local varieties for human consumption would be an alternative way of improving income and stimulating on farm conservation. The genetic variability of the total carotenoid content (TCC) of kernels in a local maize population was evaluated for their economic exploitation potential as biofortified food. Two independent samples of 96 half-sib families (HSF) plus four checks were evaluated in two groups of experiments in western SC and each one was carried out in two environments. They were set out in a 10 × 10 partially balanced lattice with three replications per location; plots consisted of one row, 5.0 m long with 1.0 m between rows. TCC ranged from 11 to 23 µg g-1, averaging ≈16 µg g-1 in the pooled analysis over the two sets. The local composite population exhibited genetic variability in order to increase the TCC of grains in the second cycle of selection by the convergent-divergent scheme.

Sugarcane (Saccharum sp.) is one of the most important crops in Brazil. The high demand for sugarcane-derived products has stimulated the expansion of sugarcane cultivation in recent years, exploring different environments. The adaptability and the phenotypic stability of sugarcane genotypes in the Minas Gerais state, Brazil, were evaluated based on the additive main effects and multiplicative interaction (AMMI) method. We evaluated 15 genotypes (13 clones and two checks: RB867515 and RB72454) in nine environments. The average of two cuttings for the variable tons of pol per hectare (TPH) measure was used to discriminate genotypes. Besides the check RB867515 (20.44 t ha-1), the genotype RB987935 showed a high average TPH (20.71 t ha-1), general adaptability and phenotypic stability, and should be suitable for cultivation in the target region. The AMMI method allowed for easy visual identification of superior genotypes for each set of environments.

The sugarcane cultivar RB937570 is early to medium maturing. It should be grown preferably on medium texture soils with medium to high fertility. In central-southeastern Brazil, RB937570 should be harvested between May and August. It is tolerant to the major economically relevant crop diseases, has a good shoot development after mechanical harvesting and high sucrose yields.

O objetivo deste trabalho foi avaliar a adaptabilidade e estabilidade fenotípica de genótipos de cana-de-açúcar no estado de Minas Gerais. Foram avaliados 15 genótipos em nove ambientes. Os experimentos foram conduzidos em blocos completos casualizados, com três repetições. Para discriminar os genótipos, utilizou-se a variável TPH (toneladas de pol por hectare). Os valores corresponderam à média de dois cortes. Os resultados revelaram que a cultivar testemunha RB867515 apresentou maior adaptabilidade geral e estabilidade fenotípica, seguida pelo genótipo RB987935, que apresentou a maior média e elevada adaptabilidade geral e específica para ambientes favoráveis e desfavoráveis, podendo ser indicada para cultivo comercial.

The objective of this research was to evaluate the adaptability and phenotypic stability of genotypes of sugarcane in the state of Minas Gerais, Brazil. There had been evaluated 15 genotypes in nine environments. The experiments were conducted in a randomized block design with three replications. To discriminate the genotypes the variable TPH (tons of pol per hectare) was used. These values corresponded to the average of two cuts. The results showed that the check RB867515 presented greater general adaptability and phenotypic stability, followed by genotype RB987935, which had the highest average and high general and specific adaptability to favorable and unfavorable environments that may be suitable for commercial cultivation.