Resistance of bioenergy sorghum to Diatraea saccharalis (Lepidoptera: Crambidae) / Resistência de sorgo bioenergia à diatraea saccharalis (lepidoptera: crambidae)

This study evaluated the effects of the sugarcane borer Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) on cultivars of sweet and biomass sorghum for the selection of resistant cultivars. The present work consisted of two trials, with natural pest infestation. In the first one, 10 sweet sorghum cultivars were analyzed for the following variables: plant height, number of healthy and damaged internodes, gallery position and size, stem infestation level and soluble solids content (°Brix). In the second trial, it was analyzed 16 genotypes of high biomass sorghum, with the same variables above mentioned, in addition to the lignin, cellulose and hemicellulose contents. Among sweet sorghum genotypes evaluated, the genotype CMSXS647 stood out due to the traits: plant height, infestation level, gallery size and soluble solids content. Among the sorghum genotypes evaluated, CMSXS7030, CMSXS7012 and CMSXS7028 presented ideal characteristics for infestation level, plant height and number of lignocellulosic compounds. Such information, in addition to supporting the bioenergy sorghum breeding program, will assist in integrated pest management for sorghum cultivation.

Foram estudados os efeitos causados pela broca-do-colmo Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae), em cultivares de sorgo sacarino e biomassa visando seleção de cultivares resistentes à praga. O presente trabalho foi constituído de dois ensaios, com infestação natural da praga. No primeiro, 10 cultivares de sorgo sacarino foram analisadas quanto às seguintes variáveis: altura das plantas, quantidade de internódios sadios e com injúrias, posição e tamanho da galeria, intensidade de infestação de colmos e teor de sólidos solúveis (°Brix). No segundo ensaio, foram analisados 16 genótipos de sorgo biomassa, com as mesmas variáveis supracitadas, além dos teores de lignina, celulose e hemicelulose. Entre os genótipos de sorgo sacarino avaliados, o genótipo CMSXS647 foi o que se destacou em função das características: altura de plantas, intensidade de infestação, tamanho de galerias e teor de sólidos solúveis. Entre os genótipos de sorgo biomassa avaliados: CMSXS7030, CMSXS7012 e CMSXS7028 apresentaram características ideais para intensidade de infestação, altura de plantas e quantidade de compostos lignocelulósico. Tais informações, além de prover o programa de melhoramento de sorgo energia podem ajudar o programa de MIP para a cultura do sorgo, uma vez que o produtor conhece a suscetibilidade dos materiais escolhidos.

Lipophilic metabolite profiling of maize and sorghum seeds and seedlings, and their pest spotted stem borer larvae: A standardized GC-MS based approach.

In order to better understand the biochemical interactions and to identify new biomarkers for plant resistance against insects, we proposed a suitable lipophilic profiling method for insects and their host plants. The critical components of GC-MS based analysis are: sample amount, extraction, derivatization, temperature gradient, run time, and identification of peaks. For lipophilic metabolite profiling of maize and sorghum, and their insect pest, spotted stem borer larvae, we recommend 100 mg sample weight for seeds and insect samples (whole insect body), and 200 mg for seedlings. Maize and sorghum seeds required less time for fat extraction in comparison to their seedlings and the pest fed on these seedlings. GC-MS was standardized for better separation and intensity of peaks using different temperature gradients in the range of 180-300 C. A total of 48 lipophilic compounds encompassing various classes based on their functional groups such as fatty acids, fatty alcohols, hydrocarbons, sterols and terpenoids, vitamin derivative, etc. were separated in the seedlings (30), seeds (14), and the pest (26) in the retention time range of 3.22 to 29.41 min. This method could be useful to study nutritional aspects of different field crops in relation to various stresses apart from the analysis of lipophilic compounds for better understanding of insect-plant interactions.

Influence of inorganic n fertilizer on plant characters, yield generation and the incidence of yellow stem borer scirpophaga incertulas, walker in the field of local scented paddy cultivar tulaipanji.

To determine the effect of inorganic N fertilizer on the incidence of yellow stem borer (YSB), Scirpophaga incertulas Walker and on grain yield, yield attributes and bio-chemical characters of local paddy cultivar Tulaipanji, a field experiment for three consecutive years (2007-2009) was carried out by randomized block design in pesticide untreated field. Treatments comprised of seven different dose of inorganic N fertilizer viz 20,40,60,80,100,120,140 kg/ha respectively. Field with no fertilizer application was considered as control. In all the cases higher the doses of inorganic N fertilizer, higher would be the incidence of adult YSB population and accordingly the extent of damage was intensified. Incidence of dead heart (DH) and white head (WH) was 175.74% and 206.72% higher than the control field when the field was fertilized by 140 kg N/ha. Yield attributing characters differed considerably among the treatments. Maximum panicle length (1.71cm), Effective tiller number/ hill (62.01), filled grain number/ panicle (66.12), tiller number/hill (11.27), leaf number/hill (48.11) and leaf width (9.11 mm) was noted when the field was fertilized with 100 kg N. But no significant improvement of yield attributing characters except the number of filled grain number/ panicle was noted when the dose of fertilizer was increased after 100 kg N/ha. Insignificant variation of grain amylose and protein content, total phenol and ortho-dihydroxy phenol (OD phenol) amount under different fertilizer treatment was noted. Plant moisture content, however, was increased as the dose of N fertilizer was improved. Field application of 100 kg N/ha is thus suggested for Tulaipanji cultivation.