Artificial Shading Can Adversely Affect Heat-tolerant Lettuce Growth and Taste, with Concomitant Changes in Gene Expression

Shading has been used to produce high-quality lettuce (Lactuca sativa) in locations where production conditions are not optimal for this cool-season crop. To learn what additional benefits shading provides if heat-tolerant cultivars are used and to understand the effects of shading on growth, sensory quality, chemical content, and transcriptome profile on heat-tolerant lettuce, we grew two romaine lettuce cultivars with and without shading using 50% black shadecloth in 2018 and 2019. Shading reduced plant leaf temperatures, lettuce head fresh weights, glucose and total sugars content, and sweetness, but not bitterness, whereas it increased lettuce chlorophyll b content compared with unshaded controls. Transcriptome analyses identified genes predominantly involved in chlorophyll biosynthesis, photosynthesis, and carbohydrate metabolism as upregulated in unshaded controls compared with shaded treatments. For the tested cultivars, which were bred to withstand high growing temperatures, it may be preferable to grow them under unshaded conditions to avoid increased infrastructure costs and obtain lettuce deemed sweeter than if shaded.

Physiological and behavioral responses of feedlot sheep with and without access to artificial shade

Artificial shading is widely used to provide thermal comfort to animals and has been extensively researched due to its relationship with their welfare and performance. This study examines the physiological and behavioral traits of sheep in a feedlot system with and without access to shade. Twenty male Santa Inês × Dorper crossbred sheep with an initial average weight of 25 kg were used in the experiment. The animals were kept in two collective stalls, one of which was equipped with a polypropylene mesh shade net with 80% light interception capacity. The experiment was conducted in the feedlot of the Fazenda Escola farm at UEG, São Luís de Montes Belos Campus, state of Goiás, Brazil. Environmental indices (ambient temperature, relative humidity, temperature-humidity index), respiratory rate (RR), rectal temperature (RT) and surface temperature (ST) were measured once weekly and behavioral assessments were performed one day after the physiological assessment, between 07h00 and 19h00. The following behaviors were evaluated: feeding, rumination, rest/sleep, social, play and anomalous activities. There were no significant differences for the analyzed variables and treatments. Animals with access to shade had the following physiological results: RR - 75.06 mov. min-1; ST - 33.03 ºC; and RT - 39.21 ºC. Those without access to shade, in turn, showed the following indices: RR - 81.52 mov. min-1; ST - 33.45 ºC; and RT - 39.43 ºC. The evaluated behaviors did not differ significantly, averaging 226.11 and 225.44 min (feeding), 153.33 and 149.44 min (rumination), 341.39 and 339.72 min (rest/sleep) and 152.50 and 154.72 min (other activities) recorded in the sheep with and without access to shade, respectively. Despite the lack of differences between the analyzed responses, the animals with access to artificial shade showed greater comfort, welfare and quality of life.

Growth of yacon under artificial shading

ABSTRACT Yacon is a tuberous root cultivated in mild climate regions with high altitudes, but the crop shows the capacity to develop at low altitudes. The objective of this study was to evaluate growth rates and the partition of photoassimilates in yacon plants under different levels of artificial shading. The experiment was conducted in four shading levels (0%, 30%, 50% and 70%), and seven monthly harvests in a completely randomized design. We evaluated the accumulation of total dry mass on the whole plant and its parts; leaf area; leaf area ratio; leaf mass fraction; stem mass fraction; rhizophores mass fraction; tuberous roots mass fraction; estimates of relative growth rate, absolute growth, and net assimilation. The lower accumulation of total dry biomass and the lowest growth rates indicate that conditions of noticeable light restriction (70% shading) restrict the growth of yacon. Yacon plants grown under moderate shading levels (30 to 50%) showed greater capacity of accumulation of total biomass, directing part of this biomass to the tuberous roots, which directly reflects gains in the agronomic productivity of this crop, indicating that yacon has the potential to be associated with other crops, which promote a moderate shading.

Development of Shading Tolerant Rice Varieties Suitable for Intercropping Cultivation in Agroforestry Systems

The Indonesian government continuously strives to increase rice production in an effort to meet the staple food needs of almost 270 million people and to turn Indonesia to become a rice exporter country. One of the strategic efforts is to expand the planted area of rice outside irrigated rice areas. Upland is one of the potential areas that continues to be developed to support the increase of national rice production. While upland is not an ideal ecosystem for rice plants to grow, the opportunity to produce rice in this ecosystem is promising, especially using rice as an intercropping in plantation. This effort requires the availability of adaptive varieties to low light intensity conditions. The breeding program to develop shade-tolerant rice varieties has been carried out by the Indonesian Center for Rice Research (ICRR) through the conventional breeding program. Breeding populations were produced by crossing local varieties, national leading varieties and introduced varieties. The selection of shading adaptive lines was carried out using both artificial shading and natural shading in the target plantation areas. New shade tolerant rice varieties have been recently released, namely Rindang 1 Agritan and Rindang 2 Agritan which have the potential to be utilized by farmers for intercropping rice cultivation in the agroforestry systems.

The effects of leaf removal and artificial shading on the composition of Chardonnay and Pinot noir grapes

Aims: The aim of this study was to assess the effects of leaf removal and bunch shading on the analytical composition of Pinot noir and Chardonnay (Vitis vinifera L.) grapes suitable for making premium sparkling wine.Method and results: Total bunch defoliation (TD) and different treatments using shading nets (TD1L, TD2L and ND1L) were evaluated in comparison with a test with no defoliation and shading (ND) over three seasons in the southern part of Franciacorta, one of the most famous Italian sparkling wine regions. Micrometeorological variables, yield components, musts and grapes chemical composition were evaluated. Shading practices lead to a delay in ripening and they improve the acidic content of must, thus resulting in a potential improvement in the quality of juice suitable for producing sparkling wines. Furthermore, this particular type of vine canopy management leads to changes in the phenolic content of grapes.Conclusions: From the results obtained it was possible to underline the positive effect - delaying ripening, preserving acid concentration and reducing flavonol content - of shading on the composition of Pinot noir and Chardonnay grapes suitable for making premium sparkling wine.Significance of the study: This study shows the importance of shading, because it delays grape ripening and thereby preserves the acidic content of musts and, specifically, deals with the problem of early ripening related to the climate change now underway.

EMERGENCE, INITIAL GROWTH AND PHOTOSYNTHETIC METABOLISM OF Ormosia arborea (Vell.) Harms UNDER DIFFERENT LIGHT AVAILABILITIES

The restoration of altered and degraded ecosystems will only be successful if research studies generate biological, ecological and physiological knowledge about the species of different Brazilian ecosystems. In order to produce quality seedlings, ecophysiological knowledge of the initial phase of the species is essential, since artificial shading can interfere with the growth rate and quality of the seedling. The aim of this study was to assess the effect of different levels of shading on the emergence, initial growth and photosynthetic metabolism of Ormosia arborea. The experiment was carried out with 30% and 70% shade and in full sun. At 60 days after sowing, non-destructive (gas exchange and chlorophyll fluorescence) and destructive (growth measures) analyzes were performed. 70% shade provides greater emergence, initial growth, gas exchange and photosynthetic efficiency of PS II. Cultivation at 0% shade (full sun) is not suitable for this species.

Characteristics of growth, flowering and corm yield of iles-iles (Amorphophallus muelleri) genotypes at third growing period

Tajuddin M, Santosa E, Sopandie D, Lontoh AP. 2020. Characteristics of growth, flowering and corm yield of iles-iles (Amorphophallus muelleri) genotypes in third growing period. Biodiversitas 21: 570-577. Iles-iles (Amorphophallus muelleri Blume) is an emerging crop for producing glucomannan, and it is predominantly cultivated in agroforestry systems. The study aimed to evaluate characteristics of growth, flowering, and production of genotypes in the third growing period in order to develop new clones. The experiment used 2-year-old corm of ten genotypes, i.e. BKB, CF, CR, LSP, SB, SBM, SG-BKK, SGH, SR and STS. The corms were planted in June 2018 to May 2019 in the field under 45% artificial shading net. Plant growth was evaluated on weekly basis from bud emergence until dormant. Flowering rate was ratio the number of corms with flower to number of planted corms in each replication. Corm dry mass was measured after harvest, which was conducted at dormant stage at 46 weeks after planting. Candidate clone was selected from the highest total score of five criteria i.e. flowering rate, corm shape, corm healthiness, marketable yield, and total yield. Results demonstrated that genotypes exhibited variation in growth, flowering rates, and yield. Based on emerging time, three genotypes (SB, SGH, SG-BKK) were classified as early emergence, five genotypes (CF, CR, LSP, SBM, STS) as a medium, and two genotypes (BKB, SR) as the late emergence. All genotypes produced inflorescence at rate 1 to 52%, and 3 genotypes (CF, CR, STS) had flowering rate >20%. Five genotypes (CR, LSP, SBM, SGH, STS) had an average corm weight > 1500 g. CR and SBM genotypes produced the largest average corm weight, i.e., 2,509.33 g and 2,129.25 g, respectively, while the BKB produced the smallest one (912.94 g). All genotypes had similar dry mass content, i.e., 18.73-20.70%. The scoring evaluation recommended CR, SBM, and STS genotypes as candidates of new clones with productivity > 30 ton/ha. It needs further evaluation of selected clones in the farmer production field.