Gustavo Dias de Almeida

Molecular mapping across three populations reveals a QTL hotspot region on chromosome 3 for secondary traits associated with drought tolerance in tropical maize

Identifying quantitative trait loci (QTL) of sizeable effects that are expressed in diverse genetic backgrounds across contrasting water regimes particularly for secondary traits can significantly complement the conventional drought tolerance breeding efforts. We evaluated three tropical maize biparental populations under water-stressed and well-watered regimes for drought-related morpho-physiological traits, such as anthesis-silking interval (ASI), ears per plant (EPP), stay-green (SG) and plant-to-ear height ratio (PEH). In general, drought stress reduced the genetic variance of grain yield (GY), while that of morpho-physiological traits remained stable or even increased under drought conditions. We detected consistent genomic regions across different genetic backgrounds that could be target regions for marker-assisted introgression for drought tolerance in maize. A total of 203 QTL for ASI, EPP, SG and PEH were identified under both the water regimes. Meta-QTL analysis across the three populations identified six constitutive genomic regions with a minimum of two overlapping traits. Clusters of QTL were observed on chromosomes 1.06, 3.06, 4.09, 5.05, 7.03 and 10.04/06. Interestingly, a ~8-Mb region delimited in 3.06 harboured QTL for most of the morpho-physiological traits considered in the current study. This region contained two important candidate genes viz., zmm16 (MADS-domain transcription factor) and psbs1 (photosystem II unit) that are responsible for reproductive organ development and photosynthate accumulation, respectively. The genomic regions identified in this study partially explained the association of secondary traits with GY. Flanking single nucleotide polymorphism markers reported herein may be useful in marker-assisted introgression of drought tolerance in tropical maize.

Calcium silicate and organic mineral fertilizer increase the resistance of tomato plants to Frankliniella schultzei

Frankliniella schultzei Trybon (Thysanoptera: Thripidae) is an important pest of tomato plants. The need for more healthful foods is stimulating the development of techniques to increase plant resistance to phytophagous insects. The objective of this research was to evaluate the effect of calcium silicate and an organic mineral fertilizer, alone or in combination, on the resistance of tomato plants to F. schultzei. The treatments consisted of: control (T1), calcium silicate (T2), organic mineral fertilizer (T3), and calcium silicate with organic mineral fertilizer (T4). The mortality of nymphs of this thrips and the number of lesions on tomato leaves were evaluated after three, six, nine and 12 applications of these products. The number of F. schultzei individuals and of lesions on tomato leaves was lower in treatments T2 and T4 than in T1 and T3, showing a possible increase in tomato resistance to this pest. The increase in the number of applications of calcium silicate and the organic mineral fertilizer increased the mortality of nymphs and reduced the damage by this insect on tomato leaves, mainly after nine applications.

QTL Mapping of Agronomic Waterlogging Tolerance Using Recombinant Inbred Lines Derived from Tropical Maize (Zea mays L) Germplasm

Waterlogging is an important abiotic stress constraint that causes significant yield losses in maize grown throughout south and south-east Asia due to erratic rainfall patterns. The most economic option to offset the damage caused by waterlogging is to genetically incorporate tolerance in cultivars that are grown widely in the target agro-ecologies. We assessed the genetic variation in a population of recombinant inbred lines (RILs) derived from crossing a waterlogging tolerant line (CAWL-46-3-1) to an elite but sensitive line (CML311-2-1-3) and observed significant range of variation for grain yield (GY) under waterlogging stress along with a number of other secondary traits such as brace roots (BR), chlorophyll content (SPAD), % stem and root lodging (S&RL) among the RILs. Significant positive correlation of GY with BR and SPAD and negative correlation with S&RL indicated the potential use of these secondary traits in selection indices under waterlogged conditions. RILs were genotyped with 331 polymorphic single nucleotide polymorphism (SNP) markers using KASP (Kompetitive Allele Specific PCR) Platform. QTL mapping revealed five QTL on chromosomes 1, 3, 5, 7 and 10, which together explained approximately 30% of phenotypic variance for GY based on evaluation of RIL families under waterlogged conditions, with effects ranging from 520 to 640 kg/ha for individual genomic regions. 13 QTL were identified for various secondary traits associated with waterlogging tolerance, each individually explaining from 3 to 14% of phenotypic variance. Of the 22 candidate genes with known functional domains identified within the physical intervals delimited by the flanking markers of the QTL influencing GY and other secondary traits, six have previously been demonstrated to be associated with anaerobic responses in either maize or other model species. A pair of flanking SNP markers has been identified for each of the QTL and high throughput marker assays were developed to facilitate rapid introgression of waterlogging tolerance in tropical maize breeding programs.

FERTILIZANTE ORGANOMINERAL E ARGILA SILICATADA COMO INDUTORES DE RESISTÊNCIA Á VARÍOLA DO MAMOEIRO

A variola ou pinta preta e um dos mais serios problemas para cultura do mamoeiro e seu controle e baseado na aplicacao excessiva de produtos quimicos. O objetivo deste trabalho foi avaliar o efeito da aplicacao de fertilizante organomineral e argila silicatada na inducao de resistencia a variola em plantas de mamao, avaliando-se a incidencia e severidade. Os tratamentos receberam aplicacoes foliares do fertilizante organomineral (T2), argila silicatada (T3), fertilizante organomineral mais argila silicatada (T4) e agua na testemunha (T1). As avaliacoes foram realizadas 5 dias apos a 6a, 9a e 12a aplicacao foliar dos produtos. Os tratamentos 2, 3 e 4 proporcionaram significativa reducao da incidencia e severidade da doenca. Contudo, maior reducao da incidencia e severidade foi observada quando se associou fertilizante organomineral mais argila silicatada (T3). A aplicacao destes produtos e uma medida eficaz e economicamente viavel para o manejo da variola em cultivos de mamao.

SURVIVAL AND REPRODUCTION OF Podisus nigrispinus (HETEROPTERA: PENTATOMIDAE): EFFECTS OF PREY SCARCITY AND PLANT FEEDING

The spined soldier bug Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a generalist predator that can alternatively feed on plant tissue to survive under prey scarcity. This research aimed to evaluate the effects of plant feeding forced by a shortage of prey on the survival and reproduction of P. nigrispinus on Eucalyptus urophylla S.T. Blake�(Myrtaceae)�plantsinthefield.� Podisus nigrispinus adults were enclosed on branches of eucalyptus by using gauze bags. These adults were fed daily with Tenebrio molitor pupae (T1) or after 5 (T2), 10 (T3) or 15 (T4) days from mating to simulate prey shortage. The pre-oviposition period, number of egg masses, number and viability of eggs and longevity of females were evaluated. Females of P. nigrispinus had a longer pre-oviposition period and produced lower number of egg masses as the period of prey shortage increased. However, the average number of eggs per egg mass, emergence of nymphs and longevity of P. nigrispinus females were not affected by prey shortage. Females of P. nigrispinuscansurvive�15�dayswithoutpreybyfeedingoneucalyptusleavesandifitfindsprey� afterwards can still reproduce. This shows that plant feeding is a successful incidental strategy to survive periods of foodscarcity�(andthusincreasetheefficiency)�ofthispredatorasabiologicalcontrolagent.

FERTILIZANTE ORGANOMINERAL COMO INDUTOR DE RESISTÊNCIA CONTRA A COLONIZAÇÃO DA MOSCA BRANCA NO FEIJOEIRO

The potential for resistant Bemisia tabaci populations to develop as a consequence of intensive use of chemical insecticides has stimulated studies on integrated pest management tactics, for example, the induction of host-plant resistance.The objective of this work was to evaluate the effect of the biofertilizer in the resistance induction in bean to the whitefly. Tests were accomplished with free-choice and no-choice tests of oviposition preference of the insect in cultivating of carioca bean. The design was completely randomized, with four treatments, being accomplished a general application in the soil, except for witness. After the first definitive pair�s of leaves appearance the applications were road leaf, being the treatments in the following way: 1, witness, 2) just an application in the soil, 3) an application in the soil one more application to foliate, 4) an application in the soil more two applications foliate. The biofertilizer caused negative effect in the population of the whitefly for the reduction of the oviposition. In that way, that product can be efficient in the handling of the whitefly in bean plantings.

DETERMINAÇÃO DA CONCENTRAÇÃO LETAL MÉDIA (CL 50) DE BEAUVERIA BASSIANA PARA O CONTROLE DE BREVICORYNE BRASSICAE

The cabbage aphid is one of the main curses of Brassicas in general, and the search for healthier foods has been stimulating the development of techniques inside of the maintainable handling, as the microbial control. The objective of this work was determine concentrations of the microbial B. bassiana for the handling of the cabbage aphid. Nymphs of B. brassicae were inoculated in submerged cabbage leaves in fungic suspensions , of the commercial product Boveril®, in the concentrations of 0.05, 0.08, 0.12, 0.31, 0.50, 1.0, 1.5, 2.0 grams per liter of distilled water plus adhesive espalhante Hai-Teem®, and maintained 26.0 ± 1.0°C and UR of 75.0 ± 5%. There was an increment of the mortality in function of the increase of the concentration, because, to smallest concentration (0.05g/L) it presented reduced effect of control 14% of confirmed mortality. However, the concentrations of 1.0-2.0g/L of water provided a superior mortality of 85%. The value found for CL50 was of 0.233g/L. In that way the microbial control of the cabbage aphid can be economical and biologically viable for the handling of this pest in brassicas cultivations.

DESENVOLVIMENTO DO SISTEMA RADICULAR DO RABANETE EM CONDIÇÃO DE ESTRESSE HÍDRICO

O objetivo desse trabalho foi avaliar o desenvolvimento do sistema radicular de plantas de rabanete, cultivar VIP Crimson Selecao Especial submetido ao estresse hidrico em diferentes fases fenologicas. O experimento foi conduzido dentro de casa de vegetacao, localizado no Centro de Ciencias Agrarias da Universidade Federal do Espirito Santo (CCA-UFES), Alegre-ES, Brasil (latitude 20° 45’S e longitude 41° 30’W). Para realizar as avaliacoes, mantiveram-se plantas de rabanete em vasos de polietileno de 4,5 L de substrato. O delineamento experimental foi o inteiramente casualizado no esquema de parcela subdividida 4x5, com 4 repeticoes, sendo cada vaso considerado como uma repeticao, a qual foi composta por tres plantas de rabanete. Os tratamentos na parcela foram estresse hidrico nas fases II; III e IV, respectivamente, denominados D7; D14 e D21 e, a testemunha D0 que foi irrigada durante todo o ciclo da cultura. Na subparcela foram feitas avaliacoes ao 7°; 14°; 21°; 28° e 35° dia para comprimento da maior raiz e avaliacoes ao 28° e 35° dia para diâmetro do bulbo. O estresse hidrico diminui significativamente o diâmetro do bulbo e a materia fresca da raiz, reduzindo a producao final em torno of 50%. Para o comprimento da maior raiz nao houve diferenca significativa ao final do ciclo da cultura.

GERMINAÇÃO E CRESCIMENTO DE MUDAS DE BIRIBAZEIRO {ROLLINIA MUCOSA(JACK) BAILL} NO BRASIL

O objetivo deste trabalho foi avaliar diferentes tratamentos pre-germinativos e tamanho de recipientes na germinacao e crescimento inicial das mudas de Rollinia mucosa (Jack) Baill . Em casa de vegetacao, o delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 3x3, sendo tres tipos de tubetes [(T1 = 288cm3, T2 = 115cm3, T3 = 55cm3)] e tres tratamentos pre-germinativo (TPG) das sementes [imersao em agua por 12 horas (AGUA), escarificacao mecânica (ESC) e testemunha sem tratamento (SS)], com 5 repeticoes de 20 sementes por parcela. No experimento conduzido em laboratorio, utilizou-se o delineamento inteiramente casualizado com nove tratamentos pre-germinativos e quatro repeticoes com 25 sementes por parcela. Os tratamentos pre-germinativos foram: imersao em acido giberelico (GA3) por 24 horas nas concentracoes de 250 (T1), 500 (T2), 750 (T3) e 1000 (T4) mg. L-1, imersao em agua por 24 horas (T5); escarificacao com acido sulfurico concentrado, por 5 (T¨6), 15 (T7), 25 (T8) e 35 minutos (T9). A germinacao das sementes de biriba para as condicoes deste experimento nao e influenciada pelos tratamentos pre-germinativos e pelos tipos de tubetes empregados. O tratamento com acido geberelico influenciou positivamente na porcentagem de germinacao e no indice de velocidade de germinacao das sementes de biriba.