Lia Mara Moterle

Componentes genéticos de médias e depressão por endogamia em populações de milho-pipoca

Ten popcorn populations (PR 038, PR 079, RR 046, SC 016, PR 017, BRS ANGELA, SC 002, PR 009, PR 023 and SE 013) were evaluated to estimate inbreeding depression and average genetic components. The experiment was a split plot in a randomized complete block design with three replications. The plots were the inbreeding levels (S1 and S0) and the sub-plots were the populations in two locations (Maringa and Iguatemi-PR) during the 2001/2002 grown season. Plant and ear height, grain yield and popping expansion were evaluated. It was observed lower values of inbreeding depression and predominance of additive effects for popping expansion in relation to yield. The sucess of getting high popping expansion inbred lines is higher with BRS ANGELA and SC 002 populations.

Diallel analysis of leaf disease resistance in inbred Brazilian popcorn cultivars.

We estimated general and specific combining abilities and examined resistance to northern leaf blight (Exserohilum turcicum) and to gray leaf spot (Cercospora zeae-maydis) in a set of nine inbred popcorn lines. These inbreds were crossed in a complete diallel scheme without reciprocals, which produced 36 F(1) hybrids. Two experiments with a square lattice design and three replications were conducted during the 2008/2009 crop season, in Maringá, PR, Brazil. The severity of northern leaf blight and gray leaf spot was assessed under natural infestation conditions. Data were examined by individual and joint analysis of variance. Individual and joint Griffings diallel analyses were carried out for adjusted means. General combining ability and specific combining ability were significant (P < 0.10) by the F-test for northern leaf blight and gray leaf spot infestation levels. This denotes that additive and non-additive gene effects both contributed to resistance to these diseases, but that the additive gene effects were more important. Among the inbred lines, P(8) and P(9) gave the highest resistance to northern leaf blight, and P(3) and P(4.3) gave the highest resistance to gray leaf spot. The hybrids P(7.4) x P(8) and P(4.3) x P(9) could be exploited by reciprocal recurrent selection to provide genotypes with both northern leaf blight and gray leaf spot resistance. Significant interaction between general combining ability and crop season (P < 0.10) denotes the importance of environment, even though the disease levels in the hybrids were quite consistent.

Influência do estresse hídrico sobre o desempenho fisiológico de sementes de híbridos simples de milho-pipoca

Objetivou-se, neste trabalho, avaliar o efeito do estresse hidrico induzido por polietileno glicol, na qualidade fisiologica das sementes de catorze hibridos simples de milho-pipoca. Para tanto, foi conduzido um experimento em que as sementes foram colocadas para germinar em substrato de papel-toalha, umedecido com solucoes de polietileno glicol (PEG 6000), nos niveis de potencial osmotico de zero (controle) e -0,3 MPa. A qualidade fisiologica das sementes foi avaliada por meio do teste de germinacao (primeira contagem e contagem final), do comprimento da raiz primaria e da parte aerea das plântulas e da biomassa seca das plântulas. A diminuicao do potencial hidrico do substrato e prejudicial a germinacao das sementes e, principalmente, ao crescimento das plântulas de milho-pipoca. Os decrescimos nas variaveis analisadas dependeram dos hibridos avaliados. Os hibridos G e K foram os que se mostraram mais tolerantes ao estresse hidrico, enquanto que o hibrido M foi mais susceptivel a seca. A tolerância ao estresse hidrico independe da qualidade inicial das sementes de milho-pipoca.

Efeito de biorregulador na germinação e no vigor de sementes de soja

Os biorreguladores vegetais sao substâncias que podem incrementar o crescimento e o desenvolvimento vegetal e estimular a divisao celular, podendo interferir na germinacao das sementes. Assim, neste trabalho objetivou-se avaliar a qualidade fisiologica de sementes sob a acao de biorregulador . Utilizaram-se sementes de nove cultivares comerciais de soja (Glycine max (L.) Merrill) e tres concentracoes (400; 500 e 600 mL 100 kg -1 de sementes) do biorregulador Stimulate®, alem da testemunha, constituida de tratamento com agua destilada. Testes de germinacao e de vigor foram realizados em sementes, observando-se a percentagem de germinacao (primeira contagem e contagem final), percentagem de plântulas normais fortes, velocidade de germinacao, comprimento da raiz primaria e da parte aerea, bem como a biomassa da materia seca das plântulas. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e quatro ou cinco repeticoes, dependendo do teste. Doses crescentes de biorregulador nao influenciaram a germinacao e a biomassa da mteria seca das sementes; entretanto, podem aumentar a velocidade de germinacao, dependendo do cultivar. Palavras-chave: Glycine max, regulador de crescimento, qualidade fisiologica.

Embriogênese somática a partir de embriões imaturos em genótipos de milho

The establishment of a protocol for regenerating plants by tissue culture is the first step in breeding programs which have the objective of using genetic transformation on plants. The plant regeneration can be achieved either by organogenesis or embryogenesis. In the second case, the somatic embryogenesis depends on the identification of responsive genotypes which enhance the efficiency of the program. The aim of the present study was to identify maize genotypes with high capacity to produce somatic embryos and consequently regenerate maize plants. Eleven genotypes (inbreds and hybrids) were investigated in the present experiment. Under two-week periods, the cultures were obtained from immature embryos which were inoculated into growing medium N6 with 690mg L-1 of proline and 10mM of 2,4-D. Callis of type II, friable and embryogenic, were observed in the LD82025, CD308, and CML314 genotypes. After, they were submitted to the regeneration process and the best performance was achieved by the LD82025. No embryogenic callus was developed from CD307, CD304, OC-705, 105-B, and GU04328. In the present case, the inbred LD82025 is the most promising maize genotype for participating in a breeding program that will use the genetic transformation of maize plants.

Combining ability of tropical and temperate inbred lines of popcorn

In Brazil, using combining ability of popcorn genotypes to achieve superior hybrids has been unsuccessful because the local genotypes are all members of the same heterotic group. To overcome this constraint, 10 lines (P(1) to P(10)) with different adaptations to tropical or temperate edaphoclimatic environments were used to obtain 45 F(1) hybrids in a complete diallel. These hybrids and three controls were evaluated in two environments in Rio de Janeiro State. Grain yield (GY), popping expansion (PE), plant height (PH), ear height (EH), and days to silking (FL) were evaluated in randomized complete blocks with three replications. Significant differences between genotypes (P <or= 0.05) were detected for GY, PE and EH. General combining ability was significant for EH, PH, PE, and GY, and specific combining ability was significant only for PE and GY. The most promising inbred lines that improved GY were P(3) and P(4), unlike P(8), P(9) and P(10), which improved PE, and P(2), which improved both PE and GY. The additive effects were much more important for PE than for GY. The hybrid combinations gave positive estimates of heterosis for GY but not for PE.

Produtividade do minimilho em função das adubações nitrogenada e potássica

Effect of nitrogen and potassium fertilization on baby corn yield There is a lack of information regarding nitrogen and potassium fertilization on the production of baby corn. When ears are collected before grain formation, the amounts of required nutrients can be differentiated. This study evaluated the response of baby corn at different nitrogen and potassium fertilization rates in a medium texture soil in the region of Maringa PR Brazil. Data for adequate nutrient recommendation are produced for the crop, avoiding losses and environmental contamination. The experiment was conducted in the Iguatemi Experimental Farm during the summer harvest of 2010-2011 and the second corn crop of 2011. The experiment was arranged in a 4x4 factorial randomized block design with a, with 4 rates of nitrogen (0, 50, 75 and 100 kg ha -1 ) and 4 rates of potassium (0, 20, 40 and 60 kg ha

COMPARAÇÃO DE TESTADORES NA AVALIAÇÃO DA CAPACIDADE DE COMBINAÇÃO DE FAMÍLIAS S2 DE MILHO-PIPOCA

The large-scale production of Baculovirus to control fall armyworm, Spodoptera frugiperda, presents many limitations. The most important limiting factor is that the baculovirus, which infects fall armyworm, causes liquefaction of the integument immediately after death. This disruption of the integument difficultates the large scale production because dead insect must be frozen before being harvested. This fact implies in high lab work need, increasing the cost of the biopesticide. This problem was overcome by the discovery of a new baculovirus nucleopolyhedrovirus (NPV) isolate in Cascavel/PR, that doesn’t cause liquefaction of the integument (isolate 6NR) immediately after the insect death. This is an extremely important factor in a large-scale baculovirus production. In addition, mortality caused by isolate 6NR on 6-day-old-larvae was above 93% (SEM=0.7%), the average weight dead larva was 116.21 mg (SEM=22.9), the larval equivalent and weight equivalent/ha were 15.04 g (SEM=1.2) and 140.32 larvae (SEM=20.1), respectively.

Qualidade fisiológica de sementes de trigo em resposta aos efeitos de anos e épocas de semeadura

The objective of this study was to evaluate the physiological quality of wheat seeds in response to the effects of years and sowing dates. In 2006 and 2007 seeds of the wheat cultivars CD 104, CD 105, CD 108, CD 110, CD 111 and CD 114 were sown on March 22nd, April 7th and 20th, May 4th and 18th, in the Palotina region, Parana State. It was analysed the following traits: germination, seedling vigor classification and accelerated ageing. The data were subjected to joint variance analysis between the two years of the experiment and cultivars, sowing dates and years, for all combinations. The germination of the cultivars CD 105 and CD 108 were less influenced by sowing dates in both crop years. The results from germination tests, classification of seedling vigor and accelerated ageing showed that the sowing periods of March 22nd, April 7th and May 18th, in 2006, were not ideal for cultivars CD 110, CD 111 and CD 114. Most sowing dates and cultivars in 2007 showed higher percentages of normal seedlings than for 2006. Furthermore, most of the cultivars showed greater similarity between the years for the April 20th sowing date according to the results of the tests for germination and classification of seedling vigor.