Genome-Wide Analysis of the HSP20 Gene Family and Expression Patterns of HSP20 Genes in Response to Abiotic Stresses in Cynodon transvaalensis

African bermudagrass (Cynodon transvaalensis Burtt–Davy) is an important warm-season turfgrass and forage grass species. Heat shock protein 20 (HSP20) is a diverse, ancient, and important protein family. To date, HSP20 genes have not been characterized genome-widely in African bermudagrass. Here, we confirmed 41 HSP20 genes in African bermudagrass genome. On the basis of the phylogenetic tree and cellular locations, the HSP20 proteins were classified into 12 subfamilies. Motif composition was consistent with the phylogeny. Moreover, we identified 15 pairs of paralogs containing nine pairs of tandem duplicates and six pairs of WGD/segmental duplicates of HSP20 genes. Unsurprisingly, the syntenic genes revealed that African bermudagrass had a closer evolutionary relationship with monocots (maize and rice) than dicots (Arabidopsis and soybean). The expression patterns of HSP20 genes were identified with the transcriptome data under abiotic stresses. According to the expression profiles, HSP20 genes could be clustered into three groups (Groups I, II, and III). Group I was the largest, and these genes were up-regulated in response to heat stress as expected. In Group II, one monocot-specific HSP20, CtHSP20-14 maintained higher expression levels under optimum temperature and low temperature, but not high temperature. Moreover, a pair of WGD/segmental duplicates CtHSP20-9 and CtHSP20-10 were among the most conserved HSP20s across different plant species, and they seemed to be positively selected in response to extreme temperatures during evolution. A total of 938 cis-elements were captured in the putative promoters of HSP20 genes. Almost half of the cis-elements were stress responsive, indicating that the expression pattern of HSP20 genes under abiotic stresses might be largely regulated by the cis-elements. Additionally, three-dimensional structure simulations and protein–protein interaction networks were incorporated to resolve the function mechanism of HSP20 proteins. In summary, the findings fulfilled the HSP20 family analysis and could provide useful information for further functional investigations of the specific HSP20s (e.g., CtHSP20-9, CtHSP20-10, and CtHSP20-14) in African bermudagrass.

Effects of overseeding times on different warm-season turfgrasses: Visual turf quality and some related characteristics

The sustainability of warm-season turfgrass species in winter dormancy is a major concern in Mediterranean ecology. The concept of overseed a lawn has been still new for many developing countries such as Turkey as part of a regular maintenance. Therefore, a 2-year study was conducted at the experimental fields of Ege University, Izmir/Turkey during 2014-2016 years to compare the effects of four different overseeding times (September 15, September 30, October 15 and October 30) on four warm season turfgrass species (Cynodon dactylon cv. SR9554, Cynodon dactylon × Cynodon transvaalensis cv. Tifway-419, Paspalum vaginatum cv. Sea Spray and Zoysia japonica cv. Zenith) by measuring visual turf quality (1-9 score) and some related characteristics as texture (mm), cover (1-9 score), weed infestation (1-9 score) and colour (1-9 score). ‘50% cv. Troya+50% cv. Esquire’ perennial ryegrass (Lolium perenne L.) mixture was used for overseeding in trial. According to results, visual turf quality performance of 6.0 scores and above were obtained from all treatments. We concluded that October 15 should be most suitable time for overseeding applications. Additionally, L. perenne L. can be practiced successfully in Mediterranean region in order to eliminate the concerns of warm-season turfgrasses in the winter dormancy period observed in cold temperatures. Highlights - No gaps were formed in plots and high coverage degrees were maintained during overseeding periods in all treatments. - Homogeneous spring transition was occurred from Lolium perenne L. to warm-season turfgrass species in all overseeding times. - Visual turf quality performance of 6.0 scores and above which is acceptable level were obtained from all overseeding times. - Better results were obtained from overseeding applications on Paspalum vaginatum and Cynodon dactylon × Cynodon transvaalensis. - The different results among the warm-season turfgrass species can provide effective information for future research studies.

Immediate Irrigation Improves Turfgrass Safety to Postemergence Herbicides

Summer annual grassy weeds such as goosegrass (Eleusine indica L. Gaertn.) continue to be problematic to control selectively with postemergence (POST) herbicides within turfgrass stands. In recent years, reduced performance by certain herbicides (e.g., foramsulfuron), cancellation of goosegrass-specific herbicides (e.g., diclofop-methyl), and cancellation and/or severe use reductions of other herbicides [e.g., monosodium methanearsonate (MSMA)] have limited the options for satisfactory control and maintenance of an acceptable (≤30% visual turfgrass injury) turfgrass quality. Currently available herbicides (e.g., topramezone and metribuzin) with goosegrass activity typically injure warm-season turfgrass species. The objectives of this research were to evaluate both ‘Tifway 419’ bermudagrass [Cynodon dactylon (L.) Pers. ×Cynodon transvaalensis Burtt-Davy] injury after treatment with POST herbicides, and to determine whether irrigating immediately after application reduces turfgrass injury. Treatments were control (± irrigation); topramezone (Pylex 2.8C; ± irrigation); carfentrazone + 2,4-D + dicamba + 2-(2-methyl-4-chlorophenoxy) propionic acid (MCPP) (Speedzone 2.2L; ± irrigation); carfentrazone + 2,4-D + dicamba + MCPP in combination with topramezone (± irrigation); metribuzin (Sencor 75DF; ± irrigation); mesotrione (Tenacity 4L; ± irrigation); simazine 4L (±irrigation); and mesotrione + simazine (± irrigation). Irrigated treatments were applied immediately with a hand hose precalibrated to apply 0.6 cm or 0.25 inch (≈6.3 L). Visual turfgrass injury for combined herbicide treatments for the irrigated plots was 6% 4 days after treatment (DAT), 12% 1 week after treatment (WAT), 17% 2 WAT, and 6% 4 WAT, whereas nonirrigated plots had turfgrass injury of 14% at 4 DAT, 31% 1 WAT, 35% 2 WAT, and 12% 4 WAT. Irrigated pots had normalized differences vegetative indices (NDVI) ratings of 0.769 at 4 DAT, 0.644 at 1 WAT, 0.612 at 2 WAT, and 0.621 at 4 WAT, whereas nonirrigated plots had the lowest (least green) turfgrass NDVI ratings of 0.734 at 4 DAT, 0.599 at 1 WAT, 0.528 at 2 WAT, and 0.596 at 4 WAT. These experiments suggest turfgrass injury could be alleviated by immediately incorporating herbicides through irrigation.

Effect of sprigging density and foliar nitrogen on the growth of Bermuda grass (Cynodon dactylon L. Pers. x Cynodon transvaalensis)

Turf grasses have been utilized by humans to enhance their environment for more than 10centuries. Aesthetically, lawns enhance the quality of life, contribute to social harmony andcommunity pride, increase property values and compliment other landscape plants. The beautyof any garden largely depends on the greenness of the lawn. The first and foremost criteria fora well establishment and a satisfactory lawn are selection of suitable grass species and methodsof its establishment. Hence, an experiment was laid out to study the effect of different spriggingdensity and foliar nitrogen on the growth and establishment of bermuda grass (Cynodon dactylonL. Pers. x Cynodon transvaalensis) in floriculture unit of the Department of Horticulture, Facultyof Agriculture, Annamalai University, Tamil Nadu during the year 2013-2015. Bermuda grasssprigs were planted in different spacing levels and foliar spray of urea with twelve treatmentcombinations comprising of different levels viz., 10 x 10 cm with 1%, 1.5% and 2%; 15 x 15 cmwith 1%, 1.5% and 2%; 20 x 20 cm with 1%, 1.5% and 2%; 25 x 25 cm with 1%, 1.5% and2%, in factorial randomized block design with three replications. From the results, it wasfound that the earliest spread and ground cover were observed in planting sprigs at closerspacing of 10 x 10 cm in combination with foliar application of nitrogen in the form of urea as2 % for two times at seven and fifteen days after planting.