No abstract

In Indonesia, maize has a number of growth constraints and one of which is climate factor. The objective of this research was to determine the growth response of local maize variety. This research was conducted by applying a factorial Randomized Block Design (RBD) with two factors. The first factor is variety (V): pulut, siropu and jakaring (comparison) while the second factor is drought treatment (K) which comprises three treatments including control, drought for 45-55 days after planting (DAP), and drought for 55-65 DAP. In this case, all treatments are repeated three times. The research revealed that the growth of maize indicate different responses towards variety as shown by parameters of plant height, soil moisture content, cob diameter, cob length, cob weight with husks, cob weight without husks, dry weight of root, and number of cob row. Meanwhile the drought stress does not indicate significant response towards growth of maize the drought-tolerant variety of maize with parameter of number of cob raw is siropu local maize.Key words: staple food; local corn; drought stress; growth.

The aim of this study was to determine the vegetative growth response of Gorontalo local upland rice Ponda Merah accession against drought and shade stresses. The study was conducted in Sipatana Village, West Bulotadaa Subdistrict, Gorontalo City, from May to October 2017, examined using randomized block design with 4 replications. The first factor observed was the drought treatment which consisted of two levels; irrigation until the inundation height of 1.5 cm and irrigation carried out if the potential of groundwater reaches - 30 to -35.9 kPa. The second factor was shades which consisted of 3 levels; 0% shade, 25% shade, and 50% shade. The results showed that Gorontalo local upland rice Ponda merah accession was able to adapt well to drought stress, shade stress, and combination of both which were characterized by high values of plant dry weight 49,88 g under drought stress condition, 84,08 g under 50% shade condition and 44,61 g in drought + 50% shade condition and chlorophyll content 0.148 mg.g−1 under drought stress condition, 0,168 mg.g−1 under 50% shade condition and 0,202 mg.g−1 in drought +50% shade condition.

Crop growth and production are strongly affected by abiotic and biotic stresses. Survival rate frequently been used to evaluate rice drought tolerance with a low survival rate of rice plants undergoing drought stress leading to low yields. The aim of this research was to obtain Gorontalo local upland rice variants that are tolerant against drought and shade stresses by considering the morphological and physiological characteristics. The research was conducted in Bulotada Barat Village, Sipatana District, Gorontalo, from January to August 2017. Employing the randomized block design with three replications, the research consisted of two treatment factors. The first factor is the accession, which consists of two tolerant accessions; two moderately tolerant accessions, two drought-sensitive accessions, and two shade-sensitive accessions. The second factor pertains to the drought and shade stresses which consist of drought + 25% shade stress, drought + 50% shade stress, and a control. Irrigation in the drought control specimen was given until inundation reached 1.5 cm. In a drought-stressed situation, irrigation was given when the groundwater reached -30 to -35.9 kPa. The Ponda Merah accessions were the accessions that were tolerant against drought and shade stresses. The morphological characteristics of Gorontalo local upland rice that showed tolerance against drought and shade stresses were longer roots (33.20 cm), heavier dry weight (38.82 gr), a thinner leaf (186,56 cm2.g-1), and a higher yield (4,90 gr.cluster−1). The physiological characteristic of the Gorontalo local upland rice that showed tolerance against drought and shade stresses was the sugar content (0,73 g.g-1) which was higher than the other treatment.

The aim of this research is to find out the tolerance level of Gorontalo local upland rice against drought stress given during the germination stage with vigor index and normal sprout dry weight variables as the indicators. The research was conducted in June 2016 using a completely randomized factorial design with four replications. The first factor is twenty-three varieties of Gorontalo local upland rice, while the second factor is 0%, 5%, 10%, and 20% PEG 6000 concentrations. The categorization of accessions to tolerant, moderate, and resistant groups is conducted based on sensitivity index test results. The research results show that based on the normal sprout dry weight, vigor index, and growth simultaneity parameters, Sonu, Ponda Merah, Ponelo, and Bulotonu accessions are tolerant against drought stress at 20% PEG concentration.