Comprehensive evaluation of the agronomic traits and forage production performance of Elymus nutans in the Qinghai-Tibet Plateau zone

Research was initiated in 1965 to identify and incorporate genes for high tiller number into midwestern six‐rowed barley, Hordeum vulgare L. The objective of this paper is to report on the performance, especially yield, of barleys with high tiller and head number from this program. Cyclic crossing, primarily backcrossing, and selection were used to develop high tillering lines that had agronomic promise. When the source of high tiller number was a two rowed barley, XH‐263, lines were evaluated after four cycles (Exp. 1) and seven cycles (Exp. 2) of breeding and when the source of high tiller number was six rowed Sel. 6194‐63, lines were evaluated after four Cycles of breeding (Exp. 2). Good progress in incorporating the genes for high tillering into a good genetic background was achieved using cyclic crossing and selection. High tillering lines developed in Exp. 1, had better agronomic performance than XH‐263, but they were lower yielding than the checks. However, in Exp. 2, the high tillering parents, Minn 73‐129 and Minn 75‐61, were nearly equal to the checks, Minn 34 and Minn 38, in yield and mean yields of individual high tiller number lines exceeded the checks, although not significantly. In Exp. 2, four groups of lines which differed in tiller number had similar yields. In both experiments, high tillering lines were high in head number and tiller mortality, low in kernel number per head and kernel weight, and susceptible to lodging. Because of high tiller mortality, breeding for increased tiller number was only 36% effective in terms of adding additional heads. We plan to continue this breeding effort since improvement in yield was achieved in the high tillering lines during the several cycles of breeding.

Solomon sengon is a provenance of sengon that grows faster than other local sengon species. The species is often cultivated in an agroforestry system, which can be combined with rice as the staple food in Indonesia. Competition between those two components to obtain the sunlight and nutrients is getting higher as sengon grows. LIPI and IPB have discovered several rice varieties. However, there has not been much research done on agroforestry between Solomon sengon (Falcataria moluccana) and rice (Oryza sativa) varieties. This study aimed to analyze the growth of Solomon sengon at 14 months old and the productivity of several rice varieties. This study used a completely randomized factorial design with two factors, namely the tree spacing factor of Solomon sengon type F2 (1.5 m × 3 m and 1.5 m × 1.5 m) and the factor of upland rice varieties (LIPI Go 1, LIPI Go 2, and IPB 9G) also lowland rice (IPB 3S). Parameters observed were sengon growth and rice productivity. Data were analyzed statistically using the analysis of variance (ANOVA) test and the Duncan test with a confidence interval of 95%. The results showed that the 14-month-old Solomon sengon with a tree spacing of 1.5 m × 3 m has a higher diameter, height, and canopy area than a tree spacing of 1.5 m × 1.5 m. The rice varieties of LIPI Go 1, LIPI Go 2, IPB 9G, and IPB 3S planted under 14-month-old sengon with a tree spacing of 1.5 m × 3 m have higher productivity than rice planted under sengon with a tree spacing of 1.5 m × 1.5 m. Rice varieties significantly affected several rice growth parameters. IPB 3S has the optimum growth and production in this study. IPB 3S is the variety with the highest number of tillers per clump and the highest number of productive tillers per clump. IPB 3S is the variety with the highest number of tillers per clump and the highest number of productive tillers per clump. Keywords: agroforestry, rice, Solomon sengon, tree spacing

Improving forage yield and quality remains a major concern of the producer. Among the various ways of supplying nutrient to the crops, the efficient utilization of nutrients by the plants is made through foliar application. Foliar application had significant effect on plant height, the number of leaf, the number of tiller, LAI, fresh forage yield, dry leaf yield, dry stem yield, total dry yield, dry leaf weight/dry stem weight ration and ash percentage. Application methods of micronutrients are very important to attain the best absorption. The results of this study demonstrated that, Fe, Zn and Mn had positive effect on yield and quality of forage sorghum. The highest plant height, LAI, Fresh forage yield, dry leaf and stem yield, total dry yield and dry leaf weight/dry stem weight was obtained in Zn+Fe+Mn application. The highest number of tiller was related to combination of Zn and Mn. The maximum ash percentage and appropriate protein percentage also was achieved in application of Zn+Fe+Mn. So, on the basis of the results, it seems that application Zn+Fe+Mn was suitable to gain high forage yield and gain to high quality.

No-till establishment of alfalfa (Medicago sativa L.) has increased significantly over the past decade, yet few studies have documented the effect of herbicide use at establishment on notill establishment-year yield and forage quality. Studies conducted in Michigan in 1989 and 1990 compared alfalfa establishment by conventional and no-tillage methods. Four establishment herbicide treatments (no herbicide, paraquat, paraquat + 2,4-DB, paraquat + EPTC + 2,4-DB) were compared with-in each tillage system. Treatments were evaluated by determining alfalfa plant population, forage yield, species composition, forage quality, and net economic return

Effects of grazing intensity on leaf photosynthetic rate (Pn), specific leaf area (SLA), individual tiller density, sward leaf area index (LAI), harvested herbage DM, and species composition in grass mixtures (Clinelymus nutans + Bromus inermis, Elymus nutans + Bromus inermis + Agropyron cristatum and Elymus nutans + Clinelymus nutans + Bromus inermis + Agropyron cristatum) were studied in the alpine region of the Tibetan Plateau. Four grazing intensities (GI), expressed as feed utilisation rates (UR) by Tibetan lambs were imposed as follows: (1) no grazing; (2) 30% UR as light grazing; (3) 50% UR as medium grazing; and (4) 70% UR as high grazing. Leaf Pn rate and tiller density of grasses increased (P < 0.05), while sward LAI and harvested herbage DM declined (P < 0.05) with the increments of GI, although no effect of GI on SLA was observed. With increasing GI, Elymus nutans and Clinelymus nutans increased but Bromus inermis and Agropyron cristatum decreased in swards, LAI and DM contribution. Whether being grazed or not, Elymus nutans + Clinelymus nutans + Bromus inermis + Agropyron cristatum was the most productive sward among the grass mixtures. Thus, two well‐performed grass species (Elymus nutans and Clinelymus nutans) and the most productive mixture of four species should be investigated further as the new feed resources in the alpine grazing system of the Tibetan Plateau. Light grazing intensity of 30% UR was recommended for these grass mixtures when swards, LAI, herbage DM harvested, and species compatibility were taken into account.

The construction of artificial grasslands using native species is an effective measure to restore degraded grassland. In this study, three native grass species, Elymus nutans, Elymus tangutorum and Poa albertii subsp. poophagorum, domesticated in the northern Tibetan Plateau were used as test subjects. Three monocultures of E. nutans, E. tangutorum and P. albertii subsp. poophagorum and four mixed combinations E. nutans +E. tangutorum, E. nutans +P. albertii subsp. poophagorum, E. tangutorum +P. albertii subsp. poophagorum and E. nutans + E. tangutorum + P. albertii subsp. poophagorum were set up, with 7 sowing types as the main zones, and nested fertilization and non-fertilization as the secondary zones. The optimal sowing combinations were selected to clarify the community growth dynamics of different grass pasture, and to investigate the transgressive overyielding and diversity effects of artificial grassland and the response of soil chemometrics to fertilizer application, with a view to providing a scientific basis for ecological restoration of degraded grassland in the northern Tibetan Plateau. The results show that the different sowing combinations of grassland all exhibit obvious dynamic population change in the growing season, with aboveground biomass peaking on 20 September. The type of E. nutans is the dominant community of the mixed combinations. The forage yield was highest in the combination, and the fertilization treatment significantly increased the forage yield. E. nutans + E. tangutorum + P. albertii subsp. poophagorum mixed sowing with fertilizer application is the recommended methodology to establish artificial grassland in the northern Tibetan Plateau. The relative yield totals of the mixed combinations were all greater than 1, and all were transgressive overyielding. Combined with the analysis of the distribution of soil ecological stoichiometric characteristics under fertilizer and non-fertilizer treatments, it was found that aboveground biomass and transgressive overyielding coefficients responded to soil ecological stoichiometry in completely different ways. Under the unfertilized treatment, soil C, N and P are regulated primarily through microbial stoichiometry under the resource dependence of soil dissolved nutrient stoichiometry, which affected aboveground of artificial grassland. Under the fertilizer treatment, microbially mediated extracellular enzyme stoichiometry was dynamically changing to regulate the new substrate environmental supply and demand balance derived from fertilizer application. Future studies should examine the long-term impacts of these combinations across diverse environments by integrating complementary restoration techniques to improve artificial grassland sustainability, thereby offering scientific support for regional ecological restoration efforts.

The study was conducted to determine the effect of different grass species (Brachiaria mutica, Desho, and Napier) and harvesting stages on agronomic performance, forage dry matter yield, and chemical composition. The grass species used were Desho (Pennisetum pedicellatum), Brachiaria (Brachiaria mutica), and Napier (Pennisetum purpureum), and the harvesting stages considered were 60, 90, and 120 days after establishment of grasses, respectively. The data collected included the following: percent plant survival (PS), plant height (PH), number of tillers per plant (NTPP), number of leaves per plant (NLPP), leaf length per plant (LLPP), leaf width per plant (LWPP), number of nodes per plant (NNPP), leaf-to-stem ratio (LSR), dry matter yield (DMY), and chemical composition of the grass species. Samples of grass species were harvested at different ages after establishment, weighed, and dried, and then, ground subsamples were taken for determination of dry matter (DM), ash, organic matter (OM), crude protein (CP), crude protein yield (CPY), acid detergent fiber (ADF), neutral detergent fiber (NDF), and acid detergent lignin (ADL). Results showed that morphological characteristics, forage dry matter yield, and chemical composition of the forage grasses were significantly affected by interactions of species ( P &lt; 0.001 ) and harvesting dates. The highest mean PH (115.2 cm), DMY (11.8 t/ha), and %CP (11.6) were recorded from Brachiaria mutica grass which was followed by Napier grass with mean PH of 87.25 cm and mean DMY of 9.8 t/ha. The %CP content of Desho and Napier grasses declined by 24%, while %CP content of Brachiaria grass declined by 26% with increased harvesting stages. Therefore, among tested grass species, Brachiaria mutica grass was recommended followed by Napier and Desho grass for on-farm evaluation and demonstration in the study area at all harvesting ages. Farmers engaged in forage grass production could seriously consider the harvesting stage as the grasses responded differently to the chemical composition.

SummaryLimited information exists on approaches to effectively revegetate severely disturbed, barren, subgrade (unconsolidated parent material) serpentine substrates. Additionally, little is known about the invasion potential of exotic grasses from highly invaded non‐serpentine environments into adjacent, relatively uninvaded serpentine environments following restoration efforts that use substrate nutrient enrichment to accelerate revegetation. This study investigated approaches to the revegetation of subgrade serpentine substrates with native, serpentine‐tolerant grass species while limiting the establishment and reproduction of invasive annual grass species.Biomass production was measured for two native serpentine perennial grass species and both biomass and seed production (fitness) were measured for one native annual and two invasive annual grass species. All species were grown on subgrade serpentine substrate amended with garden (yard) waste compost, slow‐release nitrogen (N), phosphorus (P) and potassium (K) fertilizers and CaSO42H2O (gypsum) in both glasshouse and field environments. The primary goals of this study were to: (i) determine how substrate amendment with compost changed with time and (ii) identify the substrate amended combination that maximized native grass species biomass and seed production while limiting the productivity of invasive annual grass species.Compost amendment of the subgrade serpentine substrate greatly increased plant‐available N, P, K and calcium (Ca) levels, decreased plant‐available heavy metals, and increased the cation exchange capacity. Substrateconcentration remained low for up to 60 days following compost amendment but then increased more than six‐fold in the 120 days thereafter. No other substrate properties changed substantially over a period of 180 days.Amendment of the serpentine substrate with 30% volume compost per volume substrate, and 220 mg each of N, P and K per kg substrate, maximized biomass and seed production of the native grass species. This amendment level, however, resulted in an undesirable increase in biomass and seed production (fitness) of invasive annual grass species, exceeding that of the native species.Synthesis and applications.Revegetation of drastically disturbed, barren, subgrade serpentine substrates with native, serpentine‐tolerant plant species can be successfully achieved with a combination of yard waste compost (organic) and slow‐release (inorganic) fertilizer amendment. Enrichment of low‐fertility serpentine substrates to promote native plant growth, however, may encourage invasion of undesirable plant species into the native plant community, leading to habitat degradation. Therefore, aggressive control methods may be required to prevent invasion of exotic species into the revegetation community.

光照强度和肥力变化对对垂穗披碱草生长的影响

This research was conducted in Parippung Village, Barebbo District, Bone Regency, South Sulawesi Province from January to June 2022. This study aims to determine the effect of gamma ray radiation on changes in the characteristics of the local rice plant Ase Buluh generation M5 and determine the best dose to obtain plant mutant which has the shortest stem height and produces high yields. This research was carried out in the field in the form of an experiment consisting of 3 replications and 3 treatments, namely 0 Gray, 200 Gray, 300 Gray with irradiated gamma rays. Each treatment was repeated 3 times so that there were 9 experimental units and arranged based on a randomized block design where the parameters were plant height, number of tillers, number of productive tillers, flowering age, harvest age, panicle length, number of grains, dry grain weight. per plot and dry grain weight per hectare. The results showed that the use of gamma ray radiation with various doses could significantly affect changes in the characteristics of plant height, flowering age, harvest age, but had no significant effect on the number of tillers, number of productive tillers, panicle length, number of grains, dry grain weight per plot and dry grain weight per hectare. In the 300 Gray treatment, the shortest plant height was 176.41 cm, the fastest flowering age was found in the 200 Gray treatment, which was 72 days and the fastest plant harvest age was in the 200 Gray treatment, which was 102 days. The highest number of tillers were found in the treatment of 200 Gray, namely 16.67 tillers, the number of productive tillers was 15.47 tillers, for the longest panicle was found in treatment of 300 Gray which was 64.73 cm. In treatment 300 Gray had the highest number of grains, namely 223 grains. Meanwhile, the highest yield of dry grain weight per plot and dry grain weight per hectare was found in the 0 Gray treatment, respectively, namely 1.369.6 grams and 6.85 tons.

Machine traffic and conventional tillage can cause structural degradation of the soil, affecting the physical attributes and, consequently, the production and longevity of the sugarcane field. The objective of this study was to evaluate the production components of sugarcane cultivars (RB965902, RB985476, RB966928, RB855156, RB975201, RB975242, RB036066 and RB855536) and physical attributes of a Dystroferric Red Latosol (Oxisol) under no-tillage and reduced-tillage systems. The experiment was conducted using a completely randomized experimental design in an 8 × 2 factorial arrangement, with four replicates. The soil attributes evaluated were density, total porosity, macroporosity, microporosity and penetration resistance. The production components evaluated were stalk length and diameter, number of tillers (NT), tons of cane per hectare (TCH), sucrose content (Pol), tons of sucrose per hectare (TPH), soluble solids content (Brix), total recoverable sugars (TRS) and plant fiber. Cultivars RB965902, RB966928, RB855156 and RB985476 have productivity and technological attributes that are superior to the other cultivars, whereas these are lower for RB036066 in both soil tillage systems. Cultivars RB966928, RB855156, RB975242 and RB855536 exhibited higher TCH and TPH in the no-tillage system, and all cultivars displayed equal or higher performances than those observed in the reduced-tillage system. In the no-tillage system, which exhibits lower penetration resistance values between wheel tracks and in the subsurface layer of the planting row (0.20–0.40 m), cultivars RB985476 and RB975242 had a higher NT, and RB855156 had higher stalk lengths and NT.

Allelopathy is an important process in plant communities, but the role of seed allelopathy in natural ecosystems remains poorly understood. In the present study, we examined the potential allelopathic effects of Ligularia virgaurea (a dominant species in degraded Tibetan grasslands) seeds on the germination of four native grass species (Festuca sinensis, Agrostis gigantean, Bromus inermis, and Elymus nutans). The results showed that L. virgaurea seeds can have potential allelopathic effects on seed germination, mean time to germination and root growth rates of native grass species. We further demonstrate that these effects are driven by a water‐soluble seed leachate. Species with smaller seeds were generally more sensitive than larger seeded species. The results suggest that seed‐to‐seed allelopathic potential may be an important mechanism driving the dominance of L. virgaurea in degraded alpine grasslands on the Tibetan Plateau. Further studies are required to demonstrate effects of seed‐to‐seed potential allelopathy in a field setting.

Lemongrass (Cymbopogon flexuosus) agronomic traits, oil yield and oil quality under different agro-ecological zones

Introduced grass species such as standard crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes] are most often used to revegetate degraded rangelands in the Inter mountain region of the western USA. Use of native grass species is rising because public land management policies increasingly favor plant materials representative of native flora. Our objective was to compare the population T‐21076, a promising source of germplasm of the native thickspike wbeatgrass [Elymus lanceolatus subsp. lanceolatus (Scribner &amp; Smith) Gould] [Syn‐Elytrigia dasystachya (Hook.) A. Löve &amp; D. Löve], with ‘Hycrest’ crested wheatgrass for forage yield, tiller number, and tiller weight during and after establishment. The relative importance of tiller number and tiller weight for forage yield production was compared using path coefficient analysis. Seedlings were transplanted from a greenhouse to three field environments corresponding to three moisture stress levels where six harvests were evaluated through two growing seasons. Tiller number was more affected by moisture stress than tiller weight. Forage yield production of the caespitose Hycrest was more stable under moisture stress than the rhizomatous T‐21076. T‐21076's forage yield depended mostly on tillering through rhizomatous spread, which was more sensitive to moisture stress than the tillering of Hyerest. Tiller weight of T‐21076 was similar in all environments and was equal or lower than Hycrest's at all harvests. In contrast to T‐21076, Hycrest's forage yield production relied primarily on tiller weight, a more stable trait than tiller number. Increases in Hycrest's tiller weight were able to partially compensate for reductions in its tiller number with increasing moisture stress. The advantages conferred by T.21076's rhizomatous spreading and resultant tillering are probably limited by their sensitivity to moisture stress.

Ischaemum rugosum Salisb. commonly known as ribbed murainagrass is a problematic herbicide-resistant weed in directseeded rice systems. To evaluate the competitive ability of rice cultivars against I. rugosum, a study was established with two rice cultivars (Mestiso 21, a hybrid and IR 64, an inbred). These cultivars were sown at density of 4 plants per pot with four different densities of I. rugosum (0, 2, 4, and 8 plants pot(-1)). Across weed density levels, IR 64 had 14% lower while Mestiso 21 had 20% higher plant height than I. rugosum. In competition with eight I. rugosum plants per pot, Mestiso 21 had 17% higher plant height (85 cm) than of IR 64 (73 cm). Without competition, IR 64 had higher tiller number, leaf number, leaf area, and root biomass than Mestiso 21 while in competition with eight weed plants per pot, Mestiso 21 had higher leaf biomass (29%), stem biomass (13%), specific stem length (38%), panicle biomass (29%), florets number (41%), and florets biomass (36%) than IR 64. In comparison with control (no weed competition), weed densities of 2, 4, and 8 plants pot(-1) reduced the total rice biomasses and grain yields by 32, 42, and 50%; and 26, 46, and 56% for IR 64 and by 23, 37, and 45%; and 20, 28, and 42% for Mestiso 21, respectively. The Mestiso 21 reduced the I. rugosum plant height, number of tillers, leaf biomass, inflorescence biomass, root biomass, and total aboveground biomass by 16.3, 0.3, 22.1, 31.3, 21.8, and 22.7%, respectively, compared with IR 64. The results of this study suggest that the hybrid rice Mestiso 21 has a better competitive ability to suppress I. rugosum than IR 64 therefore can be used in an integrated weed management of problematic weeds in direct-seeded rice systems.