The effect of wheat straw residue on the emergence and early growth of sugar beet (Beta vulgaris) and oilseed rape (Brassica napus)

The management of straw residue can be a concern in non-inversion tillage systems where straw tends to be incorporated at shallow depths or left on the soil surface. This can lead to poor crop establishment because straw residue can impede or hinder crop emergence and growth. Small container-based experiments were undertaken using varying amounts of wheat straw residue either incorporated or placed oil the soil surface. The effects on (lays to seedling emergence, percentage emergence, seedling dry-weight and soil temperature using sugar beet and oilseed rape were investigated because these crops often follow wheat in a cropping sequence. The position of the straw residue was found to be the primary factor in reducing crop emergence and growth. Increasing the amount of straw residue (from 3.3 t ha(-1) to 6.7 t ha(-1)) did not show any consistent trends in reducing crop emergence or growth. However, in some instances, results indicated that an interaction between the position and the amount of straw residue Occurred particularly when the straw and seed was placed on the soil surface. Straw placed on the soil surface significantly reduced mean day-time soil temperature by approximately 2.5 degrees C compared to no residue. When the seed and straw was placed on the soil Surface a lack of seed-to-soil contact caused a reduction in emergence by approximately 30% because of the restriction in available moisture that limited the ability for seed imbibition. This trend was reversed when the seed was placed in the soil, but with straw residue still on the soil surface, because the surface straw was likely to reduce moisture evaporation and improved seed-to-soil contact that led to rapid emergence. In general, when straw was mixed in or placed on the soil surface along with the seed, sugar beet and oilseed rape emergence and early growth biomass was significantly restricted by approximately 50% compared to no residue. The consequences of placing seed with or near to straw residue have been shown to cause a restriction in crop establishment. In both oilseed tape and sugar beet, this could lead to a reduction in final crop densities, poor, uneven growth and potentially lower yields that could lower financial margins. Therefore, if farmers are planning to use non-inversion tillage methods for crop establishment, the management and removal of straw residue from near or above the seed is considered important for successful crop establishment. (C) 2008 Elsevier B.V. All rights reserved.

The potential to intensify sulforaphane formation in cooked broccoli (Brassica oleracea var. italica) using mustard seeds (Sinapis alba)

Sulforaphane, a naturally occurring cancer chemopreventive, is the hydrolysis product of glucoraphanin, the main glucosinolate in broccoli. The hydrolysis requires myrosinase isoenzyme to be present in sufficient activity; however processing leads to its denaturation and hence reduced hydrolysis. In this study, the effect of adding mustard seeds, which has a more resilient isoform of myrosinase, to processed broccoli was investigated with a view to intensify the formation of sulforaphane. Thermal inactivation of myrosinase from both broccoli and mustard seeds was studied. Thermal degradation of broccoli glucoraphanin was investigated in addition to the effects of thermal processing on the formation of sulforaphane and sulforaphane nitrile. Limited thermal degradation of glucoraphanin (less than 12 %) was observed when broccoli was placed in vacuum sealed bag (sous vide) and cooked in a water bath at 100 ºC for 8 and 12 min. Boiling broccoli in water prevented the formation of any significant levels of sulforaphane due to inactivated myrosinase. However, addition of powdered mustard seeds to the heat processed broccoli significantly increased the formation of sulforaphane.

High-throughput root phenotyping screens identify genetic loci associated with root architectural traits in Brassica napus under contrasting phosphate availabilities

Background and Aims: Phosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quantitative trait loci (QTL) associated with these traits, under low Pi (LP) and high Pi (HP) availability in Brassica napus. Methods: Root architectural traits were characterized in seedlings of a double haploid (DH) mapping population (n = 190) of B. napus 'Tapidor' x 'Ningyou 7' (TNDH) using high-throughput phenotyping methods. Primary root length (PRL), lateral root length (LRL), lateral root number (LRN), lateral root density (LRD) and biomass traits were measured 12 d post-germination in agar at LP and HP. Key Results: In general, root and biomass traits were highly correlated under LP and HP conditions. 'Ningyou 7' had greater LRL, LRN and LRD than 'Tapidor', at both LP and HP availability, but smaller PRL. A cluster of highly significant QTL for LRN, LRD and biomass traits at LP availability were identified on chromosome A03; QTL for PRL were identified on chromosomes A07 and C06. Conclusions: High-throughput phenotyping of Brassica can be used to identify root architectural traits which correlate with shoot biomass. It is feasible that these traits could be used in crop improvement strategies. The identification of QTL linked to root traits under LP and HP conditions provides further insights on the genetic basis of plant tolerance to P deficiency, and these QTL warrant further dissection.

Genetical and comparative genomics of Brassica under altered Ca supply identifies Arabidopsis Ca-transporter orthologs

Although Ca transport in plants is highly complex, the overexpression of vacuolar Ca2+ transporters in crops is a promising new technology to improve dietary Ca supplies through biofortification. Here, we sought to identify novel targets for increasing plant Ca accumulation using genetical and comparative genomics. Expression quantitative trait locus (eQTL) mapping to 1895 cis- and 8015 trans-loci were identified in shoots of an inbred mapping population of Brassica rapa (IMB211 × R500); 23 cis- and 948 trans-eQTLs responded specifically to altered Ca supply. eQTLs were screened for functional significance using a large database of shoot Ca concentration phenotypes of Arabidopsis thaliana. From 31 Arabidopsis gene identifiers tagged to robust shoot Ca concentration phenotypes, 21 mapped to 27 B. rapa eQTLs, including orthologs of the Ca2+ transporters At-CAX1 and At-ACA8. Two of three independent missense mutants of BraA.cax1a, isolated previously by targeting induced local lesions in genomes, have allele-specific shoot Ca concentration phenotypes compared with their segregating wild types. BraA.CAX1a is a promising target for altering the Ca composition of Brassica, consistent with prior knowledge from Arabidopsis. We conclude that multiple-environment eQTL analysis of complex crop genomes combined with comparative genomics is a powerful technique for novel gene identification/prioritization.

Exploring the effects of genotypical and phenotypical variations in bitter taste sensitivity on perception, liking and intake of brassica vegetables in the UK

Brassicaceous vegetables (BV) have chemoprotective effects and yet consumption of BV in the UK is low. Previous studies suggest perception, liking and intake of BV are influenced by bitter taste sensitivity which this study further explores. Phenotypical taste sensitivity of 136 subjects was classified using propythiouracil (PROP) and sodium chloride and fungiform papillae density (FPD) was measured from tongue images. Polymorphisms of TAS2R38 and gustin (CA6) genes were analysed. Liking and bitterness of four raw vegetables (two BV (broccoli and white cabbage) and two non-BV (spinach and courgette)), as well as habitual consumption, were evaluated. There was a significant association between TAS2R38 genotype and PROP taster status (p<0.0001) and between FPD and PROP taster status (p=0.029). Individuals with greater sensitivity for PROP predominantly had TAS2R38 PAV/PAV genotype and greater FPD. BV were perceived as more bitter than non-BV (p<0.0001) with PAV/PAV subjects perceiving significantly stronger bitter intensity. There was a significant difference in liking for the four vegetables (p=0.002), and between consumers of different TAS2R38 genotype (p=0.0024). Individuals with TAS2R38 AVI/AVI genotype liked BV more. Regarding intake, both PAV/PAV and AVI/AVI individuals consumed more total vegetables and BV than PAV/AVI. Although PROP nontasters tended to consume more vegetables and BV than the other two phenotype groups, liking and vegetable intake were not significantly affected by taste phenotype. Although there was not a significant effect of CA6 genotype on bitterness ratings, there was a significant interaction between CA6 and TAS2R38, and in addition CA6 genotype was significantly associated with BV intake. However, these effects require validation as the proportions of the population with the CA6 G/G genotype was extremely small (7%). Our results confirmed that bitter taste perception in vegetables was influenced by both genotype and phenotype of bitter taste sensitivity. Moreover, our findings demonstrated that neither genotype nor phenotype of taste sensitivity alone accurately predict vegetable liking and intake as demographic factors were found to have a substantial influence.

High-throughput phenotyping (HTP) identifies seedling root traits linked to variation in seed yield and nutrient capture in field-grown oilseed rape (Brassica napusL.)

Background and Aims Root traits can be selected for crop improvement. Techniques such as soil excavations can be used to screen root traits in the field, but are limited to genotypes that are well-adapted to field conditions. The aim of this study was to compare a low-cost, high-throughput root phenotyping (HTP) technique in a controlled environment with field performance, using oilseed rape (OSR; Brassica napus) varieties. Methods Primary root length (PRL), lateral root length and lateral root density (LRD) were measured on 14-d-old seedlings of elite OSR varieties (n = 32) using a ‘pouch and wick’ HTP system (∼40 replicates). Six field experiments were conducted using the same varieties at two UK sites each year for 3 years. Plants were excavated at the 6- to 8-leaf stage for general vigour assessments of roots and shoots in all six experiments, and final seed yield was determined. Leaves were sampled for mineral composition from one of the field experiments. Key Results Seedling PRL in the HTP system correlated with seed yield in four out of six (r = 0·50, 0·50, 0·33, 0·49; P < 0·05) and with emergence in three out of five (r = 0·59, 0·22, 0·49; P < 0·05) field experiments. Seedling LRD correlated positively with leaf concentrations of some minerals, e.g. calcium (r = 0·46; P < 0·01) and zinc (r = 0·58; P < 0·001), but did not correlate with emergence, general early vigour or yield in the field. Conclusions Associations between PRL and field performance are generally related to early vigour. These root traits might therefore be of limited additional selection value, given that vigour can be measured easily on shoots/canopies. In contrast, LRD cannot be assessed easily in the field and, if LRD can improve nutrient uptake, then it may be possible to use HTP systems to screen this trait in both elite and more genetically diverse, non-field-adapted OSR.

Efeito de sinigrina aplicada em folhas de brássicas sobre características biológicos de Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Impacto de inimigos naturais e de fatores meteorológicos sobre uma população de Brevicoryne brassicae (L.) (Hemiptera: Aphididae) em couve

Neste estudo, visou-se avaliar o impacto de inimigos naturais e de fatores meteorológicos na população do pulgão Brevicoryne brassicae (L.), na cultura da couve, usando-se correlação simples e análise de regressão múltipla com seleção de variáveis pelo método stepwise. A amostragem de B. brassicae foi realizada por procura visual e dos inimigos naturais através de armadilhas de sucção e de solo. Formas ápteras de B. brassicae começaram a infestar a couve em julho, atingindo pico populacional em setembro. Os fatores que apresentaram correlação significativa com a população de B. brassicae, no período que abrangeu todo o levantamento populacional, foram Diaeretiella rapae (Mc'Intosh), aranhas presentes no solo, precipitação pluviométrica e umidade relativa, sugerindo que tais fatores tiveram função importante na mortalidade do pulgão. No período de maior crescimento e declínio populacional de B. brassicae, aranhas presentes no solo mostraram-se como o fator de mortalidade mais significativo relacionado com a variação da densidade populacional do pulgão.

Nutritional composition, phenolic compounds, nitrate content in eatable vegetables obtained by conventional and certified organic grown culture subject to thermal treatment

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Calcium bioavailability from the kale (Brassica-oleracea) consumed as a complement of a basal rice and bean diet

The bioavailability of calcium from the kale (Brassica oleracea var. acephala) consumed as a complement of a basal rice and bean diet was studied. Three groups of diets, two controls and one experimental were fed to Wistar female rats. The protein source of the first control was casein and of the second, a mixture of bean and rice. To both groups, graded levels of CaCO3 were added. The experimental diet was similar to the second control, except that CaCO3 was substituted for kale supplying the same amount of calcio. At 35 days of experimental period, they were killed and the calcium and phosphorus were determined in the right femur. The results indicated that the calcium from the kale is better utilized than that of the CaCO3. There was no significant difference in the concentration of calcium in the soft tissues studied among three dietary groups. Considering the high concentration and availability of calcium from the kale its consumption as a complement of the basal rice and bean diet may be recommended as a cheap and good source of this mineral.

Flutua_̧tiao populacional de formas aladas de Brevicoryne brassicae (L.) (Hemiptera: Aphididae)

Studies related with the flight activity of aphids captured with traps can be useful to predict the appearance of alate forms in the field. It is also useful to understand the population dynamics of those insects. This work was carried out at the Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, State of São Paulo, during the period from July 1997 to December 1999, aiming to determine the population curve of alate Brevicoryne brassicae (L.) in the region of Jaboticabal and the influence meteorological factors plays on it. The population survey was carried out in four places, and the alate aphids were sampled by yellow water traps. The influence of air temperature, relative humidity, rainfall and sunshine brightness was verified using stepwise regression. The first captures of alate B. brassicae in the traps began at the end of June. In the region of Jaboticabal, the population curve of alate B. brassicae showed the highest frequency of flights during September. The appearance of alate forms in kale fields at initial stage of development was favored by maximum and minimum temperatures of 26.4°C and 13.5°C, respectively; relative humidity of 75.1%, and reduced rainfall.

Aspectos biológicos e taxa de consumo de Orius insidiosus (Say, 1832) (Hemiptera: Anthocoridae) predando Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de produtos a base de óleo de nim em diferentes formulações no controle de Plutella xylostella (L.,1758) (Lepidoptera: Plutellidae), em couve

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rice-Straw Mulch Reduces the Green Peach Aphid, Myzus persicae (Hemiptera: Aphididae) Populations on Kale, Brassica oleracea var. acephala (Brassicaceae) Plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)