Maize (Zea mays L.) is the second most commonly produced and consumed crop after wheat globally and is adversely affected by high heat, which is a significant abiotic stress factor. This study was carried out to determine the physiological and biochemical responses of hybrid corn varieties under heat stress (‘HS’) compared to control (‘C’) conditions during the 2020 and 2021 growing seasons. The experiment was conducted under natural conditions in the Southeastern region of Turkey, where the most intense temperatures are experienced. This experiment used split plots in randomized blocks with three replications, with ‘HS’ and ‘C’ growing conditions applied to the main plots and the different hybrid corn varieties (FAO 650) planted on the sub plots. Mean values of days to 50% tasseling (DT, day), grain yield (GY, kg ha−1), leaf water potential (LWP, %), chlorophyll-a (Chl-a, mg g−1), cell membrane damage (CMD, %), and total phenol content (TPC, μg g−1) were significantly different between years, growing conditions, and hybrid corn varieties. Changes in the climate played a significant role in the differences between the years and growing conditions (GC), while the genetic characteristics of the different corn varieties explained the differences in outcomes between them. The values of DT, GY, LWP, Chl-a, CMD, and TPC ranged from 49.06–53.15 days, 9,173.0–10,807.2 kg ha−1, 78.62–83.57%, 6.47–8.62 mg g−1, 9.61–13.54%, and 232.36–247.01 μg g−1, respectively. Significant correlations were recorded between all the parameters. Positive correlations were observed between all the variables except for CMD. The increased damage to cell membranes under ‘HS’ caused a decrease in the other measured variables, especially GY. In contrast, the GY increased with decreased CMD. CMD was important in determining the stress and tolerance level of corn varieties under ‘HS’ conditions. The GY and other physiological parameters of ADA 17.4 and SYM-307 candidate corn varieties surpassed the control hybrid corn cultivars. The results revealed that the ADA 17.4 and SYM-307 cultivars might have ‘HS’-tolerate genes.

Bu çalışma, 2016-2017 yılları arasında GAP Tarımsal Araştırma Enstitüsü Müdürlüğüne bağlı Koruklu istasyonlarında 20 hibrit mısır çeşidinin tane verimi ile tane özellikleri arasında ki ilişkilerin belirlenmesi amacıyla yürütülmüştür. Deneme tesadüf blokları deneme desenine göre 3 tekerrürlü olarak yürütülmüştür. Araştırmada tane verimi, koçanda tane oranı, hasat tane nemi, bitki boyu ve bazı tane özellikleri (tane protein oranı, tane nişasta oranı ve tane yağ oranı) incelenmiştir. Araştırma sonuçlarına göre; tane veriminin 972.02-1386.34 kg/da, koçanda tane oranının %0.77-0.91, hasatta tane neminin %15.27-29.47, bitki boyunun 245.15–307.36 cm, tane protein oranının %7.67–14.50, tane nişasta oranının, %58.73-76.30 ve tane yağ oranının, %3.10–8.27 arasında değiştiği belirlenmiştir. Denemenin ikinci yılında daha sıcak ve kuru hava koşullarından dolayı, birinci yıla göre ikinci yılda tane verimleri, verim öğeleri ve nişasta oranın düştüğü görülmüştür. Tane verimi ve nişasta oranlarının azaldığı mısır çeşitlerinde, protein ve yağ oranlarının artığı belirlenmiştir. Tane verimi, nişasta oranıyla pozitif bir korelasyon içerisindeyken, protein ve yağ oranlarıyla negatif bir korelasyon içerisinde olduğu tespit edilmiştir.

ÖzBu araştırma ile farklı ekim sıklığı uygulamalarının silajlık mısırın verim ve bazı verim unsurlarına etkisini belirlemek amaçlanmıştır. Araştırma 2010, 2011 ve 2012 yıllarında 3 yıl süre ile Harran Ovası koşullarında Şanlıurfa'da yürütülmüştür. Deneme tesadüf blokları deneme deseninde 3 tekrarlamalı olarak kurulmuştur. Samada-07 silajlık mısır çeşidi bitkisel materyal olarak kullanılmıştır. Araştırmada 14285 bitki/da (sıra üzeri 10 cm), 10204 bitki/da (sıra üzeri 14 cm), 7937 bitki/da (sıra üzeri 18 cm), 6493 bitki/da (sıra üzeri 22 cm), ve 5494 bitki/da (sıra üzeri 26 cm) olmak üzere 5 adet ekim sıklığı kullanılmıştır. Silaj verimi, kuru ot verimi, bitki boyu, sap kalınlığı, yaprak sayısı ve kuru madde oranı bakımından ekim sıklıkları arasında önemli farklılık belirlenmiştir (P≤0.01). En yüksek silaj verimi (6884 kg/da) ve kuru ot verimi (2131 kg/da) 14286 bitki/da ekim sıklığında (10 cm sıra üzeri) belirlenirken, en yüksek kuru madde oranı değeri %29.91 ile 5494 bitki/da (26 cm sıra üzeri) ekim sıklığında bulunmuştur. Effect of Different Sowing Densities to Silage Yield and Some Agricultural Characteristics of Corn (Zea mays L. indentata) in Harran Plain Conditions AbstractThis study aimed to determine effect of different sowing densities to silage yield and some agricultural characteristics of corn. Study was conducted in Harran Plain-Şanlıurfa conditions according to complete randomized block design with tree replicates in 2010, 2011 and 2012. Samada-07 dent corn silage variety was used in the study. Sowing densities were 14285 plant/da (intra row space 10 cm), 10204 plant/da (intra row space 14 cm), 7937 plant/da (intra row space 18 cm), 6493 plant/da (intra row space 22 cm) and 5494 plant/da (intra row space 26 cm). Sowing densities were significant at silage yield, dry grass yield, plant height, stem diameter, leaf number and dry matter ratio (P≤0.01). The highest silage yield (6884 kg/da) and dry grass yield (2131 kg/da) were found at 14286 plant/da (10 cm intra row space) sowing density. But the highest dry matter ratio (%29.91) was obtained from 5494 plant/da (26 cm intra row space).

Sweet corn is cultivated in different climatic regions of the world, and consumed either fresh or processed. Morpho-physiological effects of environmental stress on yield, yield components and quality of some sweet corn varieties were investigated in field experiments conducted at Southeastern Anatolia Region of Turkey during 2019 and 2020 growing seasons. The experimental lay out was randomized blocks with three replicates. Eight candidates and two control sweet corn varieties classified as moderate maturity (FAO 650–700) were used in field experiment. Mean values of pollen fertility rate (PFR, %), total soluble solids (TSS, °Brix), abscisic acid (ABA, nmol/g DW), ear length (EL, cm), plant height (PH, cm), number of grains per cob (CGN, grain) and fresh cob yield (FCY, t ha−1) were significantly different between years and sweet corn varieties. The PFR, TSS, ABA, EL, PH, CGN and FCY ranged from 40.29–67.65%, 13.24–20.09 °brix, 7.74–21.04 nmol/g DW, 9.69–15.98 cm, 97.80–171.34 cm, 289.15–420.33 grain and 4.15–10.23 t ha−1 respectively. The FCY, yield components and PFR values in the second year that had a higher temperature and lower relative humidity were lower compared to the first year, while ABA and TSS values were higher in the second year. Statistically significant correlations were recorded between the parameters investigated except FCY and TSS. The FCY and other parameters of sweet corn varieties, which produced high ABA phytohormone, were high, and the ABA hormone significantly contributed to plant growth under stress conditions. The results revealed that the PFR physiological parameter and ABA hormone in the plants provide important information about stress level and stress tolerance level of the cultivars, respectively. Despite adverse environmental stress conditions, the FCY of ŞADA-18.7 variety, one of the candidate varieties, was higher than that of the control and the mean value of the experiment.

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