Traits Dry Matter Research Articles

Natural Variation in Lignin and Pectin Biosynthesis-Related Genes in Switchgrass (Panicum virgatum L.) and Association of SNP Variants with Dry Matter Traits

Switchgrass (Panicum virgatum), a C4 perennial grass native to North America and developed as a sustainable biofuel feedstock, occurs in two ecotypes, lowland and upland, which vary in their architecture as well as their range of adaptation. In this study, we assessed single nucleotide polymorphism (SNP) variation in 372 switchgrass genotypes for nine genes involved in lignin and pectin biosynthesis. STRUCTURE results at K = 3 differentiated the genotypes into three genetic subpopulations that corresponded largely to the previously characterized upland C1 and lowland C2 and C3 subpopulations. Out of the 146 SNPs identified, 19 SNPs were non-synonymous, including two non-conservative and common SNPs in cinnamyl alcohol dehydrogenase (CAD, Chr01N) and p-coumarate3-hydroxylase (C3H, Chr09N), two genes in the lignin biosynthesis pathway. Allele status at seven of the 19 non-synonymous SNPs, including the non-conservative SNP in C3H, was significantly associated with four dry matter traits within subpopulations. Dry matter traits appeared to be mostly dominant and three of them (acid detergent fiber, non-fiber carbohydrate, water-soluble carbohydrates) were the most frequently differentiated traits. In addition, a heterosis effect was detected at the non-conservative SNP in phenylalanine ammonia-lyase (PAL) for neutral detergent fiber. Association analysis revealed the CAD gene on Chr01N, its homoeolog on Chr01K and cinnamate 4-hydroxylase (C4H, Chr03K) as potential candidates associated with dry matter traits. Further analyses are needed to determine whether these candidate genes play a role in switchgrass lignin content and could be exploited to reduce recalcitrance in this bioenergy crop.

Anti-transpirant role in improving the morphological growth traits of maize plants subjected to water stress!

A field experiment was carried out to study the role of anti-transpiration treatments in some growth and dry matter traits of maize crop growing under the water stress conditions during the two autumn seasons of 2016 and 2017. The randomized complete block design (RCBD) with split plots order was used in the study, which included three levels of water stress: depleting 50, 60 and 70% of the available water symbolized by I1, I2and I3, and equivalent to 580, 420 and 340 mm/season, respectively, where water stress represented the main factor, while the second factor was represented by the anti-transpiration treatments: Salicylic acid at 200 mg/l, Vapour Gard at 15 ml/l, Kaolin clay at 200 mg/l and Leaf sil at 15 ml/l referred to by the symbols S1, S2, S3 and S4, respectively, in addition to the control treatment S0 (without spraying). The results showed no significant differences between the two treatments of depleting 50% of the available water and depleting 60% of the water in the traits of number of days to tasseling, number of leaves, leaf area, leaf area index, plant dry matter, and crop growth rate, indicating the possibility of providing the water amount up to 1600 m3/ha in both the seasons. The plants treated by depleting 50% of the available water gave the highest average of plant height compared to the other treatments, whereas the treatment of depleting 70% of the available water gave the lowest averages of all studied traits. Spraying anti-transpiration agents increased the studied growth traits under the water stress conditions. The treatments of spraying salicylic acid, kaolin and vapour guard gave significant variations in comparison with the control treatment (without spraying).

Factors Affecting Seedling Emergence and Dry Matter Characteristics in Musa balbisiana Colla

The effects of storage duration (0, 2, 4, 6, 8, and 10 days), sterilization with sodium hypochlorite (0, 5, 10, 15, and 20%), and weaning media on seedling characteristics and dry matter content in Musa balbisiana seedlings were studied. The experiment was factorial in a completely randomized design with five replicates. The result indicates that increase in NaOCl concentration and number of days in storage significantly (P=0.5) increased the period of seedling emergence. Also, soaking in NaOCl for 20 min had significant effect on average seedling emergence at 15 and 20% concentrations, compared to 10 min soaking at the same concentrations. The combined effects of storage duration and sterilization resulted in a decrease in the duration of seedling emergence. Seeds previously sterilized with either water or NaOCl had no significant effect on seedling growth, leaf and corm dry weight, but affected almost all the dry matter traits. A mixture of poultry manure, top soil, and river sand as weaning media gave better seedling growth and increased dry matter characteristics. We conclude that M. balbisiana seeds require after-ripening treatment to enhance germination, sterilizing seeds with 5% NaOCl for 10 min and air-drying under ambient condition for 2–6 days were found most appropriate, and a mixture of poultry manure, top soil, and river sand is recommended as weaning medium for growth and dry matter composition in M. balbisiana seeds.