Chilean Journal of Agricultural Research

ABSTRACT Land for agriculture is becoming limited in urban areas and the concept of vertical farming could help increase land productivity. Therefore, this study was conducted to investigate the potential of vertical farming on sunlight availability for lettuce (Lactuca sativa L.) production in the greenhouse system. The experimental design was completely randomized design with two different farming systems: Horizontal and vertical farming systems. Ten planting shelves including five horizontal shelves (HS) and five vertical shelves (VS) with three vertical levels as upper (VS_U), middle (VS_M) and lower (VS_L) were constructed. Two lettuce varieties, ‘Green Oak’ (L. sativa var. crispa) and ‘Green Cos’ (L. sativa var. longifolia), were selected for comparative measurement. Lettuce was planted in both HS and VS systems. Photosynthetically photon flux density (PPFD) was continuously monitored throughout lettuce growing period. Lettuce height and canopy width were measured weekly. Leaf fresh weight (FW) and dry weight (DW) were also evaluated. The averaged PPFD values were 245, 217, 158 and 147 μmol m-2 s-1 for HS, VS_U, VS_M and VS_L, respectively. Higher values of height and canopy width were observed on HS in comparison to VS. Values of FW and DW on HS were significantly higher as compared to VS. In addition, higher plant growth occurred from upper to lower levels on VS while lower FW and DW were observed from top to bottom. Plant densities of VS (24 plant m-2) were 1.5 times higher than HS (16 plant m-2). Light use efficiency was also pointed out that VS (0.46 g mol-1) tended to have better values in comparison to HS (0.28 g mol-1).

ABSTRACT There is growing interest in expanding quinoa (Chenopodium quinoa Willd.) cultivation; however, the main limitation is its sensitivity to temperatures above 32-35 °C. Chenopodium berlandieri Moq., the wild-weedy North American ancestor of quinoa, was employed as an exotic source of drought, heat, and salinity tolerance to enlarge genetic variation in cultivated quinoa. The present work aims to assess the influence of high temperatures on seed setting rate and production potential of two quinoa recombinant inbred lines (RILs), RIL2-4 and RIL2-5. Thus, trials were carried out in Morocco at Berrechid and Tiflet in 2017-2018 and Bouchane, Meknès, and El Kebab in 2018-2019. The field experiment design was a randomized complete block with four replicates. Ten quantitative traits were measured. The ANOVA showed significant variability for all the evaluated parameters. The seed setting rate had widely different degrees of variation among experimental sites, exceeding 120% at Berrechid and Tiflet while approaching 98% at Bouchane. Tiflet expressed the lowest seed setting at 11.26%. Pearson’s correlation matrix analysis showed a significant positive correlation between plant size at maturity and inflorescence length. An analysis of mixed model interactions (AMMI) revealed the first interaction; principal component axis explained 53.3% of the total variation while the second axis described 46.7%. Four homogeneous groups emerged. The recombinant inbred lines have segregated for tolerance to high temperatures as evidenced by their variable seed setting rates and grain and DM yields.

ABSTRACT Agroclimatic variables in different time windows were analyzed using Artificial Intelligence techniques to estimate the fruit growing season extension and harvest start date for ‘Gala’ apples (Malus domestica (Suckow) Borkh.) Meteorology and phenology data were collected from five orchards in Central Chile, between 2004 and 2019. The attributes derived from air temperature during the first days of fruit growing season showed the high relationship with harvest start date: The number of hours below 18 °C from full bloom to 35 d after (R = 0.9) and growing degree hours accumulated from full bloom to 45 d (R = -0.84). Different models were developed with these attributes. Simple and multiple linear regression models were the most accurate for explain the length of the total fruit growth period until harvest. The 35 d after full bloom time window was the most effective, with an R2 = 0.82, for estimating harvest start date of ‘Gala’ apples. These results contribute to the apple growers demand to schedule fruit harvest and processing, especially in a climate change scenario.

ABSTRACT Drought is a major abiotic constraint on rice (Oryza sativa L.) production in Malaysia. Malaysian Agricultural Research and Development Institute (MARDI) has released more than 50 indica rice genotypes so far. However, little has been studied about their drought tolerance. The study aimed to evaluate the germination and early seedling growth performances of 15 rice genotypes under polyethylene glycol (PEG) 6000-induced drought stresses. Four osmotic potentials of PEG 6000 (0, -0.3, -0.6, -0.9 MPa) were used in the study denoted as control, low, moderate and severe stresses respectively. Data on seed germination percentage, germination index, germination energy, germination rate, seedling height, seedling vigor I and II, fresh and dry weight of seedlings were measured. Studied parameters varied greatly among genotypes with different osmotic stresses. The findings suggested most of the rice genotypes showed an apparent reduction in germination and growth traits, while MR211 showed less reduction under all of the stresses. The Multivariate clustering grouped genotypes into five different clusters, where cluster V (MR220, MR269, MR253, MR297, MR303 and MR284) incorporated six genotypes showed better germination and growth under different osmotic potentials, followed by cluster IV (MR211 and MR307). Cluster II incorporated one genotype MARDI WARNA98 which had minimal germination and growth attributes. Principal component analysis (PCA) was performed to identify the maximum contributing variables for diversity, revealed maximum variation by first two components (81.8% and 7.7%) respectively. Therefore, PEG 6000 can be used as an efficient tool for discrimination and identification of drought tolerance in rice.

ABSTRACT Tomatoes (Solanum lycopersicum L.) are the most cultivated and consumed vegetable species in the world and deserve special attention due to their nutritional and functional value. The aim of this study was to assess the nutritional value of organically grown tomatoes in greenhouses, at different maturity phases. Five hybrids were studied: Antalya F1, Cemile F1, Lorely F1, Tiger F1 and Sacher F1. The observed parameters in each harvest phase were: Content of chlorophyll a and b, total carotenoids, total soluble solids (TSS), ascorbic acid (vitamin C) and titratable acidity (TA). Taking into account the content of TSS and TA, taste and maturity index was established. Tiger F1, Sacher F1 and Cemile F1 hybrids were significantly standing out for all analysed parameters. Sacher F1 had a carotene content of 10.3 mg 100 g-1 FW in green fruit and 17.0 mg 100 g-1 FW in red fruit. Vitamin C was 6.2 mg 100 g-1 FW in green fruits, increasing to 16.0 mg 100 g-1 FW in red fruits. The mineral content depended on the hybrid and harvest stage. In the rose phase the highest K content was in Cemile F1 (151.53 mg 100-1 g), Ca in Lorely F1 (8.16 mg 100 g-1), Mg in Sacher F1 and Tiger F1 with values over 22.0 mg 100 g-1, and Tiger F1 and Sacher F1 distinguish in Zn, Cu and Fe content. In the red fruit phase, Tiger F1 and Sacher F1 hybrids are representative for almost all minerals excepting Lorely F1 and Cemile F1.