Environment comparison in the germination of sugarcane seeds

A obtenção de cariopses de cana-de-açúcar por meio de cruzamento de parentais é de primordial importância para os programas de melhoramento de cultivares. Objetivou-se, neste trabalho comparar o ambiente de germinação de cariopses da casa de vegetação do Programa Cana IAC com um ambiente de condições controladas, a fim de avaliar sua eficiência, no período de 30/09 a 09/10/2004. Foram desenvolvidos dois experimentos, em delineamento experimental de blocos casualizados com quatro repetições, em Jaú, SP. Um deles foi montado sob condições de laboratório em câmara de germinação e outro em casa de vegetação em condições não controladas, sendo cada tratamento constituído por 100 cariopses por repetição, provenientes de seis cruzamentos. Foram realizadas avaliações do índice de velocidade de germinação (IVG), da porcentagem (%G) e dos dias para emergência (DE), em intervalos de 24 horas, após a instalação dos testes. A massa de 100 sementes de cada cruzamento também foi avaliada com o propósito de verificar sua influência nos demais atributos da germinação. Os resultados foram submetidos à análise de variância e a comparação de médias foi feita pelo teste de Tukey, a 0,05 de significância. A massa de 100 sementes foi diferente entre os cruzamentos, e interferiu, de maneira geral, nos atributos IVG e % G. Concluiu-se que a casa de vegetação utilizada pelo Programa Cana IAC proporciona porcentagens de germinação semelhantes às da câmara de germinação, porém condições controladas favorecem o IVG e os DE.The production of true seeds of sugarcane through parental crossing is primordial for the breeding programs of cultivars. With the objective of comparing the efficiency of the environment greenhouse used for seed germination in the IAC Sugarcane Program with an environment with controlled conditions (germination chamber), two experiments were carried out in a completely randomized block with four replicates of 100 seeds each, in Jaú (SP), from 09/30 to 10/09/2004. In both places the treatments were composed of seeds from six crossings. The evaluations accomplished were speed of germination index (SGI), germination percentage (% G) and days for emergence (DE) in 24 h intervals after set up treatments. The mass of 100 seeds of each crossing was also evaluated with the purpose of measuring its influence on other germination attributes. The data were submitted to the analysis of variance and averages were compared by the Tukey test at 0.005 significance. The weight of 100 seeds differed among the crossings, and, in general, it interfered with the attributes SGI and % G. It was concluded that the greenhouse used by the IAC Sugarcane Program provides germination percentages similar to the germination chamber; however, controlled conditions improve SGI and DE

Estimates of genetic parameters and expected gains from selection of yield traits in sugarcane families

ABSTRACT It is essential to have basic information on the genetic nature of variation of various metric traits in plantation crops for the proper planning of breeding strategies. The objective of this paper was to estimate the variability for five yield traits in sugarcane (Saccharum spp.) families. Eighteen controlled pollination families were evaluated in a randomized complete block trial having 16 plants per linear plot at Jaú Development and Research Station (DDD/APTA/SAA), in Jau city, Sao Paulo State, Brazil. In the second year, families were assessed and harvested six months after the first ratoon, and evaluated for the following characters: stalk height, stalk diameter, average Brix, stalk number and stalk weight. The results showed highly significant (p<0.01) genetic differences among families for most traits. The genotypic variance component accounted for 4.27, 3.55, 15.87, 3.32 and 51.68% of the phenotypic variance for stalk height, stalk number, stalk diameter, stalk weight and average Brix, respectively. Heritabilities at individual plant level for the above traits were 56.57, 76.59, 67.40, 72.73 and 54.11%, respectively. Negative significant genotypic and phenotypic correlations were found between Brix and stalk height (r g = -0.78**, r p = -0.56**) and stalk diameter (r g = -0.81**, r p = -0.75**). Selecting the best two families out of 18 families would result in a genetic gain of 4.92% and 10.82% for stalk height and stalk diameter, respectively. The best two selected individual seedlings within each family would result in a genetic gain of 18.61% and 16.94% with a total gain of 23.57 % and 27.76 % for these two traits, respectively

Residual biomass potential of commercial and pre-commercial sugarcane cultivars

Sugarcane (Saccharum spp.) is an efficient and sustainable alternative for energy generation compared to non-renewable sources. Currently, during the mechanized harvest process, the straw left in the field can be used in part for the second generation ethanol and increasing the electric energy production. Thus, this study aimed to provide information on the potential for residual biomass cultivars of sugarcane cropping system. This study provides the following information: yield of straw, depending on the calculated leaf area index and the number of tillers per linear meter; primary energy production of several sugarcane genotypes; contribution of dry tops and leaves; biomass yield; and evaluation of fiber, cellulose, hemicellulose and lignin. Preliminary results obtained by researchers of the State of São Paulo, Brazil, and reCviews related studies are presented. The results suggest that the production of sugarcane straw content varies according to the cultivars; the greater mass of sugarcane straw is in the top leaves and that the potential for the crude energy production of sugarcane per area unit can be increased using fiber-rich species or species that produce more straw. The straw indexes was shown to be a good indicator and allow the estimation of straw volumes generated in a sugarcane crop. The cellulose, hemicellulose and lignin composition in sugarcane is distinct among varieties. Therefore, it is possible to develop distinct biomass materials for energy production and for the development of sugarcane mills using biochemical processes and thermal routes

Análise dialélica em clones de cana-de-açúcar

Visando avaliar a ação gênica predominante em caracteres de importância econômica da cana-de-açúcar e identificar cruzamentos com potencial genético favorável para o desenvolvimento de novos cultivares, avaliaram-se oito genótipos segundo um esquema em dialelo desbalanceado, e também, progênies de 44 cruzamentos no delineamento látice 7 x 7, com três repetições, no Centro de Pesquisa e Melhoramento da Cana-de-Açúcar (CECA), da Universidade Federal de Viçosa. Os caracteres estudados foram: Brix % caldo da cana, número de colmos, massa média de colmo, toneladas de colmos por hectare, toneladas de Brix por hectare e porcentagem de florescimento. Os resultados evidenciaram a importância tanto dos efeitos gênicos aditivos como dos não-aditivos na expressão das características avaliadas. Os genótipos SP82-6108 e IAC86-2210 e as combinações híbridas SP82-6108 x SP88-754, SP82-6108 x SP87-365, SP81-1763 x SP82-6108, IAC86-2210 x SP88-754, IAC86-2210 x SP86-96, IAC86-2210 x SP81-1763, SP88-819 x SP87-365, SP84-2029 x SP87-365 e SP88-754 x SP87-365, mostraram maior potencial para elevar a produtividade de cana-de-açúcar

Residual biomass potential of commercial and pre-commercial sugarcane cultivars

Sugarcane (Saccharum spp.) is an efficient and sustainable alternative for energy generation compared to non-renewable sources. Currently, during the mechanized harvest process, the straw left in the field can be used in part for the second generation ethanol and increasing the electric energy production. Thus, this study aimed to provide information on the potential for residual biomass cultivars of sugarcane cropping system. This study provides the following information: yield of straw, depending on the calculated leaf area index and the number of tillers per linear meter; primary energy production of several sugarcane genotypes; contribution of dry tops and leaves; biomass yield; and evaluation of fiber, cellulose, hemicellulose and lignin. Preliminary results obtained by researchers of the State of São Paulo, Brazil, and reCviews related studies are presented. The results suggest that the production of sugarcane straw content varies according to the cultivars; the greater mass of sugarcane straw is in the top leaves and that the potential for the crude energy production of sugarcane per area unit can be increased using fiber-rich species or species that produce more straw. The straw indexes was shown to be a good indicator and allow the estimation of straw volumes generated in a sugarcane crop. The cellulose, hemicellulose and lignin composition in sugarcane is distinct among varieties. Therefore, it is possible to develop distinct biomass materials for energy production and for the development of sugarcane mills using biochemical processes and thermal routes

Residual biomass potential of commercial and pre-commercial sugarcane cultivars

Sugarcane (Saccharum spp.) is an efficient and sustainable alternative for energy generation compared to non-renewable sources. Currently, during the mechanized harvest process, the straw left in the field can be used in part for the second generation ethanol and increasing the electric energy production. Thus, this study aimed to provide information on the potential for residual biomass cultivars of sugarcane cropping system. This study provides the following information: yield of straw, depending on the calculated leaf area index and the number of tillers per linear meter; primary energy production of several sugarcane genotypes; contribution of dry tops and leaves; biomass yield; and evaluation of fiber, cellulose, hemicellulose and lignin. Preliminary results obtained by researchers of the State of São Paulo, Brazil, and reCviews related studies are presented. The results suggest that the production of sugarcane straw content varies according to the cultivars; the greater mass of sugarcane straw is in the top leaves and that the potential for the crude energy production of sugarcane per area unit can be increased using fiber-rich species or species that produce more straw. The straw indexes was shown to be a good indicator and allow the estimation of straw volumes generated in a sugarcane crop. The cellulose, hemicellulose and lignin composition in sugarcane is distinct among varieties. Therefore, it is possible to develop distinct biomass materials for energy production and for the development of sugarcane mills using biochemical processes and thermal routes