- (1965-1980, 1981-1990, 1991-2000 and 2001-2012). For each grouping, the previously described factors were also estimated. A total of 110 cultivars were studied and it was concluded that the genetic base of Brazilian irrigated rice cultivars is narrow.

Genetic resistance is one of the most suitable strategies to control cucurbit powdery mildew (CPM) on melon, incited by Podosphaera xanthii or Golovinomyces orontii. However, many races of these pathogens have been reported worldwide in recent years, what may compromise the effectiveness of this method. Thus, annual surveys of CPM races and the screening of germplasm for new sources of genetic resistance provide a vital support to melon breeding programs. This study aimed at identifying a natural population of CPM race under greenhouse conditions, as well as evaluating the reaction of local and exotic melon germplasm for CPM-resistance. CPM race identity was based on the reaction of eight race differentials: Védrantais, Nantais Oblong, PMR 45, PMR 5, WMR 29, Edisto 47, PI 414723 and PI 124111. Fifty-nine melon genotypes were evaluated, 53 of them being germplasm accessions, and six net melon elite-inbred lines, besides two net melon-type cultivars (Louis and Fantasy). Plants were evaluated using a visual scale for leaf lesions. The causal pathogen was confirmed to be P. xanthii, based on the presence of fibrosin bodies in conidia and the complete resistance response of winter melon (Benincasa hispida). Race 4 was identified for the first time in the São Paulo state, Brazil. Genotypes A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 and Solarking showed to be resistant to the race 4.

In recent years, a group of small watermelons has stood out with 1-3 kg in weight called mini watermelons. These watermelons, when grown under greenhouse conditions, require different management techniques. This study evaluated the performance of mini watermelon hybrids at different plant spacing. To this end, the experiments were conducted in a greenhouse using a substrate of coconut husk fibers with fertigation. The study design was a randomized block with 5 × 3 factorial treatments and four replicates. The factors evaluated included five mini watermelon hybrids (Beni Kodama, Ki Kodama, Smile, New Kodama, and Beni Makura) and three plant spacing configurations (E 1 = 0.35 m, E 2 = 0.50 m, and E 3 = 0.65 m). Growth characteristics, production, and quality were evaluated using analysis of variance. There was no significant interaction between the hybrids and plant spacing for yield traits, physiological traits, and fruit quality. Fresh fruit mass, yield, transverse and longitudinal diameter and firmness presented significant differences for both factors, type of hybrid and plant spacing. In this study, despite the established competition in terms of spacing, the performance of hybrids was not negatively affected. Thus, we recommend the cultivation of hybrids spaced 0.50 m apart in coconut husk fibers, because it results in good yield and fruit quality, while facilitating plant management techniques.

Embora as orquídeas sejam de grande importância ambiental e econômica, há poucos estudos científicos sobre controle alternativo de doenças, que representam um grande problema para produtores e cultivadores. Uma estratégia de controle alternativo sustentável é o uso de extratos a partir de plantas. Objetivou-se com este trabalho avaliar a atividade antifúngica de extratos de plantas no controle de Rhizoctonia sp. isolado de orquídea. A partir de orquideas com quadro sintomatológico de Rhizoctonia sp., o fitopatógeno foi isolado e repicados, com posterior confirmação a nível de gênero, com base em parâmetros macro e microscópicos. Em seguida, foi avaliado o potencial antifúngico de extratos aquosos de aroeira (Schinus terebenthifolius Raddi), gauaco (Mikania glomerata Spreng), tuia (Thuja occidentalis Lineu) e gergelim (Sesamum indicum Lineu). O bioensaio foi conduzido no delineamento experimental inteiramente casualizado em esquema fatorial 4 x 3 (Quatro extratos vegetais e três doses cada). As concentrações testadas foram 0, 10 e 20%, com 15 repetições cada. Houve maior inibição micelial de Rhizoctonia sp. pelos extratos aquosos de tuia e guaco na concentração de 20%, demostrando atividade antifúngica de 19,84 e 14,74%, respectivamente.

The corn crop has been cultivated throughout the country, with increasing productivity with the help of technology products. There are greater demand and greater use of improved seeds, associated with treatments of fungicides, insecticides, and bioregulators. It is believed that the use of biostimulant can improve many plant characteristics, one of which is productivity. The present work had as objective to evaluate the effect of the use of biostimulant applied in the treatment of seeds on the germinability and initial development of corn plants. The biostimulants used in the experiment were the Haf-Plus ® from the Inesta group, which is an organomineral stimulant and Stimulate ® from Stoller do Brazil which is a hormonal bio stimulant. The experimental design was completely randomized, in a 2 x 4 factorial scheme, with two biostimulants (Stimulate ® and Haf Plus ®) in 4 doses (Stimulate: control, 0.5 mL of Stimulate + 1 mL of water, 1.0 mL of Stimulate + 0.5 mL of water, 1.5 mL of Stimulate, and for Haf Plus: control, 0.125 mL + 0.375 mL of distilled Original Research Article