Basal Tillers Research Articles

LATA1, a RING E3 ligase, modulates the tiller angle by affecting auxin asymmetric distribution and content in rice.

The tiller angle is an important agronomic trait that determines plant architecture and grain yield in rice (Oryza sativa L.). However, the molecular regulation mechanism of the rice tiller angle remains unclear. Here, we identified a rice tiller angle gene, LARGE TILLER ANGLE 1 (LATA1), using the MutMap approach. LATA1 encodes a C3H2C3-type RING zinc finger E3 ligase and the conserved region of the RING zinc finger is essential for its E3 activity. LATA1 was highly expressed in the root and tiller base and LATA1-GFP fusion protein was specifically localized to the nucleus. The mutation of LATA1 significantly reduced indole-3-acetic acid content and attenuated lateral auxin transport, thereby resulting in defective shoot gravitropism and spreading plant architecture in rice. Further investigations found that LATA1 may indirectly affect gravity perception by modulating the sedimentation rate of gravity-sensing amyloplasts upon gravistimulation. Our findings provide new insights into the molecular mechanism underlying the rice tiller angle and new genetic resource for the improvement of plant architecture in rice.

Blocking miR396 activity by overexpression MIM396 improved switchgrass tiller number and biomass yield.

MicroRNA396 (miR396) plays an important role in the regulation of plant growth and development by repressing the expression level of its target growth-regulating factor (GRF) family genes. In our previous study, we found that overexpression of miR396 negatively regulated both tillering and biomass yield in switchgrass (Panicum virgatum L.). We, therefore, speculated that blocking the expression of miR396 could enhance switchgrass tillering and biomass yield. Here, we produced transgenic switchgrass plants overexpressing a target mimicry form of miR396 (MIM396) in wild type (WT) and Os-MIR319b overexpressing switchgrass plant (with higher enzymatic hydrolysis efficiency, but reduced tillering), in which the expression of miR396 was blocked. The phenotype and biological yields of these plants were analyzed. Blocking miR396 to improve its target PvGRFs expression in switchgrass improved the tiller number and dry weight of transgenic plants. Further morphological analysis revealed that MIM396 plants increased the number of aerial branches and basal tillers compared to those of wild-type plants. The enzymatic efficiency of MIM396 plants was reduced; however, the total sugar production per plant was still significantly higher than that of wild-type plants due to the increase in biomass. In addition, blocking miR396 in a transgenic switchgrass plant overexpressing Os-MIR319b (TG21-Ms) significantly increased the PvGRF1/3/5 expression level and tiller number and biomass yield. The miR156-target gene PvSPL4, playing a negative role in aerial and basal buds outgrowth, showed significant downregulated in MIM396 and TG21-Ms. Those results indicate that miR396-PvGRFs, through disrupting the PvSPL4 expression, are involved in miR319-PvPCFs in regulating tiller number, at least partly. MIM396 could be used as a molecular tool to improving tiller number and biomass yield in switchgrass wild type and miR319b transgenic plants. This finding may be applied to other graminaceous plants to regulate plant biological yield.

Optimizing Nitrogen Fertilizer Management Enhances Rice Yield, Dry Matter, and Nitrogen Use Efficiency

Optimizing nitrogen fertilizer management can effectively improve soil ecology, promote agricultural production, and increase the income of farmers and workers. Nitrogen fertilizer is an important factor in the growth and development of rice, and it is important to find out the optimal amount and frequency of fertilizer application for the super-hybrid early rice ‘Zhu LiangYou 819’ in Hunan Province, to give full play to its high quality and high yield characteristics. Various N fertilizer application frequencies (P1, basal–tiller fertilizer = 5:5; P2, basal–tiller–spike fertilizer = 4:3:3; P3, basal–tiller–spike–grain fertilizer = 4:3:2:1) and N application amounts (N1, 90 kg ha−1; N2, 150 kg ha−1; N3, 210 kg ha−1) were applied to the hybrid rice ZLY819. The results show that, under the same frequency of N application, ZLY819 had the highest yield, agronomic efficiency, and physiological utilization rate of N fertilizer with the N2 treatment, averaging 7.53 t ha−1, 18.10 kg kg−1, and 34.34%, respectively, with the yield under N2 being 19.38% higher than that under N1. For the same amount of N application, the yield, agronomic efficiency, partial factor productivity of N (PFPN), N contribution to seed, and N use efficiency (NUE) increased with an increase in the frequency of N application, mainly in the order of P3 > P2 > P1, whereby the yield of P3 was 10.11% higher than that of P1. According to the regression equation, the yield is higher when the amount of nitrogen application is 202.15 kg ha−1 and the fertilization frequency is four times. Appropriate N fertilizer management (P3N2) improved the rice growth characteristics, dry matter accumulation, crop growth rate, dry matter transport rate, dry matter contribution rate, and NUE, thus promoting an increase in the rice yield and efficient use of nitrogen.

The effects of heat stress on male reproduction and tillering in Sorghum bicolor

AbstractDue to global climate change, heat stress is increasingly harming the growth, development, overall biomass, and grain yield of numerous crops. Heat stress impairs pollen development and thus reduces seed set in Sorghum bicolor (L.) Moench; however, the effects of heat stress on anther development at specific stages and tiller formation remain incompletely understood. Here we report that exposure to heat stress [42°C/32°C (day/night)] at pollen mother cell (PMC) and booting stages profoundly disrupts tapetum and pollen development, resulting in a significant decrease in grain yield in sorghum. Sorghum plants subjected to 9 days or less of heat stress at the PMC stage exhibited normal pollen viability, but 12 days of heat stress caused almost complete loss of grain yield and the formation of nonviable pollen grains. Similarly, sorghum plants that were heat‐stressed for 3 days at the booting stage produced few seeds. Further analysis revealed that aberrant tapetum and pollen development contributed to the sterility of pollen in these heat‐stressed plants. Notably, in addition to inhibiting plant height, a 12‐day heat stress at the PMC stage promoted the formation of basal tillers, whereas a 3‐day heat stress at the booting stage stimulated the formation of apical tillers, which helped salvage seed yield under heat stress conditions. Moreover, the application of exogenous auxin promoted the formation of apical tillers and leaf numbers per apical tiller. Collectively, our findings suggest that sorghum is susceptible to heat stress during both early and late anther development, and auxin might be involved in governing the formation of apical tillers.

Association Analysis of Tiller-Related Traits with EST-SSR Markers in Psathyrostachys juncea.

Psathyrostachys juncea is a long-lived perennial Gramineae grass with dense basal tillers and soft leaves. It is used widely in cold and dry areas of Eurasia and North America to establish grazing pasture and is even used as an ideal plant for revegetation and ecological restoration. Plant architecture, especially tillering traits, is critical for bunch grasses in breeding programs, and these traits in plants are mostly quantitative traits. In this study, the genetic diversity, population structure, and linkage disequilibrium of 480 individual lines were analyzed using 127 pairs of the EST-SSR marker, and a significant association between ten plant-architecture-related traits of P. juncea and molecular markers was found. The results of the genetic diversity analysis showed that the number of observed alleles was 1.957, the number of effective alleles was 1.682, Shannon's information index was 0.554, observed heterozygosity was 0.353, expected heterozygosity was 0.379, and the polymorphism information content was 0.300. A total of 480 individual lines were clustered into five groups based on population genetic structure, principal coordinate analysis, and unweighted pair group method with arithmetic mean analysis (UPGMA). The linkage disequilibrium coefficient (r2) was between 0.00 and 0.68, with an average of 0.04, which indicated a relatively low level of linkage disequilibrium among loci. The results of the association analysis revealed 55 significant marker-trait associations (MTA). Moreover, nine SSR markers were associated with multiple traits. This study provides tools with promising applications in the molecular selection and breeding of P. juncea germplasm.

Effect of harvest frequency and season on morphogenic and structural characteristics of dwarf and tall Elephantgrass genotypes

AbstractThis study aimed to evaluate the impact of two harvest frequencies (60 and 90 days) on the morphogenic and structural characteristics of four Elephantgrass genotypes (two tall and two dwarf) in both rainy and dry seasons. The research was conducted in Garanhuns, Brazil from September 2019 to December 2021. The morphogenic characteristics evaluated included leaf appearance rate, stem and leaf elongation rate, phyllochron, plant height, stem diameter, leaf and stem length, basal tiller population density, and number of leaves per tiller. The results showed that Elephant B had the highest leaf elongation rate among all genotypes, both in the rainy and dry seasons. During the rainy season, the tall genotypes showed higher stem elongation rates compared to the dwarf genotypes. The tall genotypes also had lower phyllochron values. Taiwan A‐146 2.37 had a higher population density of basal tillers by 30%–37% compared to other genotypes. During the dry season, the stem elongation rate of Taiwan A‐146 2.37 was slower compared to the rainy season. The study showed that the harvest frequency had an effect on the morphogenic characteristics of Elephantgrass genotypes, with 60 days harvest resulting in higher leaf elongation rates. Elephant B was superior in terms of leaf elongation at both harvest frequencies. The results indicate that the season also plays a role in the morphogenic characteristics of the genotypes. This study provides insights into the optimal cutting strategies for Elephantgrass based on the size of the plant and season.

Controlled-Release Blended Fertilizer Combined with Urea Reduces Nitrogen Losses by Runoff and Improves Nitrogen Use Efficiency and Yield of Wet Direct-Seeded Rice in Central China

Controlled-release fertilizer is one of the best fertilizer management strategies for improving the yield and nitrogen use efficiency of transplanted seedling rice. Wet direct-seeded rice has gradually replaced transplanted seedling rice since it saves labor. In addition, it is conducive to mechanization promotion. However, the effects of controlled-release fertilizers on wet direct-seeded rice remain largely unknown. A two-year field experiment aimed to compare the effects of controlled-release blended fertilizer at two rates (basal N to tiller N ratio = 7:3 (CRBF+U), CRBF alone), urea at two rates (basal–tiller ratio of 4:6 (U40), 6:4 (U60)) and a control (no N fertilizer) on the ammonia volatilization (AV) loss, nitrogen runoff loss, accumulation, transport, utilization and yield of rice. The nitrogen runoff loss in wet direct-seeded rice paddy fields was concentrated from sowing to the three-leaf and one-leaflet stage, and the loss rat was lowest after CRBF+U (11.41–12.94%). AV loss rate was lowest after CRBF (3.41%), followed by CRBF+U (3.55–3.89%). CRBF+U increased nitrogen accumulation by extending the duration of rapid nitrogen growth and accelerating maximum nitrogen growth. CRBF+U also increased the nitrogen transport rate of stems, sheaths and leaves from full heading to maturity, and intensified the increase in nitrogen in panicles, increasing the harvest index, agronomy utilization rate and apparent utilization rate of nitrogen. Finally, the grain number per panicle, seed-setting rate and actual yield of rice were significantly improved. In conclusion, CRBF+U can reduce nitrogen runoff loss and AV loss and can improve the yield and nitrogen use efficiency of wet direct-seeded rice.

Photoperiod and gravistimulation-associated Tiller Angle Control 1 modulates dynamic changes in rice plant architecture.

TAC1 is involved in photoperiodic and gravitropic responses to modulate rice dynamic plant architecture likely by affecting endogenous auxin distribution, which could explain TAC1 widespread distribution in indica rice. Plants experience a changing environment throughout their growth, which requires dynamic adjustments of plant architecture in response to these environmental cues. Our previous study demonstrated that Tiller Angle Control 1 (TAC1) modulates dynamic changes in plant architecture in rice; however, the underlying regulatory mechanisms remain largely unknown. In this study, we show that TAC1 regulates plant architecture in an expression dose-dependent manner, is highly expressed in stems, and exhibits dynamic expression in tiller bases during the growth period. Photoperiodic treatments revealed that TAC1 expression shows circadian rhythm and is more abundant during the dark period than during the light period and under short-day conditions than under long-day conditions. Therefore, it contributes to dynamic plant architecture under long-day conditions and loose plant architecture under short-day conditions. Gravity treatments showed that TAC1 is induced by gravistimulation and negatively regulates shoot gravitropism, likely by affecting auxin distribution. Notably, the tested indica rice containing TAC1 displayed dynamic plant architecture under natural long-day conditions, likely explaining the widespread distribution of TAC1 in indica rice. Our results provide new insights into TAC1-mediated regulatory mechanisms for dynamic changes in rice plant architecture.

Canopy leaf area and leaf mass in the upper stratum of Urochloa hybrid ‘Mavuno’ grass subjected to nitrogen fertilisation

AbstractNitrogen (N) inputs are recognised to maximise herbage mass (HM) in tropical perennial grasses, whereas less is clear on their impact on HM distribution and the effects on leaf mass (LM) and leaf area index (LAI) in the upper stratum. This 2 year study, carried out in Pirassununga, Brazil, assessed the HM distribution in the upper (>20 cm) and lower (<20 cm) strata in Urochloa hybrid ‘Mavuno’ grass maintained under similar pre‐ and post‐cutting canopy heights with contrasting N fertilisation rates applied after each cutting (no‐nitrogen, 15, 30, and 45 kg N ha−1). The relevance of specific leaf area (SLA), leaf N concentration (NLeaf), tiller weight (TW) and population density to the LM and LAI of the upper stratum were also examined. Mavuno grass expressed a stable HM < 20 cm (59%–71% during Year I and 66%–80% for Year II), and apparent N fertilisation impacts on HM > 20 cm were verified at specific regrowth cycles during Year II. Mavuno grass pastures expressed plasticity for adjustments on leaf, tiller and population attributes, which were modulated by both climatic conditions and N fertilisation. Under favourable growth conditions during Year I, fertilised pastures were able to sustain higher NLeaf and SLA but associated with lower TW, resulting in maximisation of LAI but not in LM in the upper stratum. During Year II, fertilised pastures expressed higher NLeaf, SLA, number of basal tillers, despite the lowest TW, which resulted in higher LAI and LM in the upper stratum compared with non‐fertilised pastures. Our results highlighted that adjustments on leaf and population attributes within the canopy were driven to maximise the upper stratum LAI, being positively affected by N fertilisation.

Spatiotemporal variation of chasmogamy and cleistogamy in a native perennial grass: fecundity, reproductive allocation and allometry.

It is difficult to assess the relative variability or stability of chasmogamous (CH) and cleistogamous (CL) reproduction in perennial herbs with mixed mating because long-term data in natural populations are unavailable. Here, the aim was to quantify and compare spatial (between-habitat) and temporal (among-year) variation in CH and CL reproduction over 5 years in two subpopulations of the native perennial grass Danthonia compressa. This species produces CH spikelets on terminal panicles in early summer, while axillary CL spikelets, including a basal cleistogene, mature into the autumn. Flowering tillers were collected from a sunny woodland edge and an adjacent shady interior habitat for 5 consecutive years (2017-21). Seed set, fecundity, seed mass and biomass allocation were recorded for the two floral types along with tiller vegetative mass. Bivariate line fitting was used for allometric analysis of CH and CL fecundity. Seed set, fecundity, mass per seed and allocation to seeds differed between floral types and showed significant variation between habitats and among years. Seed set and fecundity in CH panicles were greater than that of axillary CL panicles in most years. Tiller mass positively affected axillary CL seed production and mass of the basal cleistogene. Fecundity and allocation among years were more variable for CH compared to CL reproduction. High seed set and fecundity of CH spikelets suggest that pollination does not limit reproduction via chasmogamy. Late maturation of axillary CL spikelets provides additional fecundity, especially in larger plants along sunny woodland edges. The heavy cleistogene at the tiller base could be important to population persistence, analogous to the axillary bud bank of other perennial grasses that are not cleistogamous. The spatiotemporal stability of CL reproduction underscores the ecological significance of cleistogamy to reproductive fitness.

Productivity and nutritional value of elephant grass BRS Kurumi subjected to different proportions of defoliation

The objective of this paper was to evaluate productivity, nutritional value of forage and tillering of elephant grass cv. BRS Kurumi under different pre-defoliation and post-defoliation canopy heights (residual height). The experimental design consisted in a randomized complete block design, with four replications. Treatments corresponded to the factorial combination of two pre‐defoliation heights (60 and 80 cm) and three post-defoliation residue heights (10, 25 and 40 cm), combined in factorial design 2 x 3, being, respectively, 60 x 10 cm; 60 x 25 cm; 60 x 40 cm; 80 x 10 cm; 80 x 25 cm; 80 x 40 cm. Productive, bromatological, carbohydrate fractionation and in situ degradability characteristics were evaluated. Results indicated that if the objective is to seek short intervals between grazing, associated with higher forage quality, the 60 x 25, 60 x 40 and 80 x 40 managements are the most indicated ones. For maximum forage productivity, 80 x 10 and 80 x 25 are the most recommended ones. For tillering, a canopy height management of 80 cm is preferred, with 80 x 25 for aerial tillers and 80 x 40 for basal tillers.

CTH251 flue-cured tobacco F1 hybrid

CTH251 is a high yielding flue-cured tobacco with improved leaf quality and is comparable to the check, CTH14. It has comparatively lower percentage total alkaloids than the check. Ground sucker (basal tillers) weight for CTH251 tended to be slightly lower than for the check, which may be more of an advantage for growers when controlling suckers during early season.

Assessment of variability in sorghum [Sorghum bicolor (L.) Moench] germplasm for agro-morphological traits

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop of the semi-arid tropics. Phenotypic characterization of conserved gene bank accessions is necessary for their effective utilization for crop improvement. In this study, a total of 2834 accessions of sorghum were characterized during 2018-19 and the data were subjected to ANOVA, Pearson’s correlation analysis, and Shannon’s diversity index analysis. Shannon diversity index calculated indicated ear head shape to be the most diverse (H’=1.36). Several trait-specific accessions for early flowering (EC0524806, 57 days), high yield (IC0355254, 245.3 g/plan) etc. were identified. Pearson correlation analysis indicated that grain yield was positively influenced by the traits like ear head width (r=0.14), plant height (r=0.1), number of basal tillers (r= 0.07), and 100seed weight (r= 0.09). The trait-specific germplasm accessions identified in the study could be used as trait-specific donors by breeders for sorghum crop improvement. Keywords: Sorghum, Shannon Diversity, Correlation

Reasonable Nitrogen Regime in the Main Crop Increased Grain Yields in Both Main and Ratoon Rice

Planting ratoon rice can realize one sowing and two harvests, which is of great significance for improving grain yield. However, the effects of nitrogen (N) regime in the main crop on the grain yield of ratoon rice and the associated physiological mechanisms are not clearly understood. The indica hybrid rice Liangyou 6326 was used, and three N fertilizer levels (100 kg ha−1 (low N, LN), 250 kg ha−1 (medium N, MN), and 400 kg ha−1 (high N, HN)) and four different ratios of basal tillering fertilizer to panicle fertilizer (7:3, 6:4, 5:5, and 4:6) applied to the main crop were designed to investigate their effects on the grain yields of the main and ratoon crops. The results showed that excessive N application rate and panicle N application rate in the main crop was not conducive to the improvement of yield and agronomic nitrogen use efficiency (ANUE) in both seasons. The increased yield in the ratoon crop was attributed to the increase in the regeneration rate. Appropriate increasing of the panicle N application rate was beneficial for increasing the ROA and NSC concentration in the main crop, resulting in an increase in the number, length, and fresh weight of regenerated buds, which caused an improvement in the regeneration rate. However, when excessive panicle N was applied in the main crop, the excessive germination of regenerated buds decreased the length and fresh weight of the regenerated bud and resulted in a decrease in the regeneration rate. These results suggest that in the production of ratoon rice, reasonable N regime in the main crop could increase the yield and ANUE in both seasons.

Gas exchange and millet phytomass under organic fertilization and graywater irrigation

ABSTRACT Graywater is an alternative method to increase the water supply for agricultural production in semi-arid regions. The objective of this study was to evaluate the effects of different irrigation depths of graywater on the gas exchanges and phytomass of millet plants with and without organic fertilization. The research was conducted under greenhouse conditions in Serra Talhada municipality in semiarid region of Brazil, in a randomized complete block design with a factorial (4 × 2 + 1) plot and three replicates. The first factor corresponded to graywater irrigation depth equivalent to 25, 50, 75 and 100% of the available water content of the soil, and the second factor was the addition of bovine manure as fertilizer (0 and 34 Mg ha-1), and a control (irrigation with low-salinity water). Irrigation with graywater effluent did not promote adverse effects on gas exchanges and phytomass accumulation; however, it also did not provide enough nutrients to promote increase in these variables. The reduction in irrigation depth caused a decrease in gas exchange from 45 days after the application of the treatments. The basal tiller mass was the most favored plant component due to organic fertilization.

Genetic variability of early flowering and yield contributing traits in Barnyard Millet [Echinochloa frumentacea (Roxb). Link] grown at different altitudes

Barnyard millet is an important up surging minor millet in Asia countries for food and nutritional security. Being a minorcrop, the genetics and inheritance of the traits need to understand, for effective utilization in the crop improvementprogrammes. Here, we investigated the genetic background and inheritance of different traits in barnyard millet genotypes.Forty germplasm accessions were evaluated in different ecological environments of southern India for 17 quantitative traits.Genetic variability analysis using GENSTAT and the pooled REML mean data results revealed that Phenotypic Co-efficientof Variation (PCV) was greater than the Genotypic Co-efficient of Variation (GCV) over the diverged ecological locationsindicating the existence of environmental influence on all the biometric traits studied. In the Western Ghats region (E1),high heritability coupled with high genetic advance was exhibited for traits like days to flowering, plant height, days tomaturity, number of nodes, length of nodes, number of basal tillers, stem diameter, flag leaf length, flag leaf width,inflorescence length, inflorescence width, length of peduncle, number of racemes, single ear head weight and grain yield perplant. Traits like thousand grain weight expressed moderate genetic advance with high heritability while, length of lowerracemes expressed moderate heritability with high genetic advance. Similarly, high heritability coupled with high geneticadvance was recorded for all the characters in valley region (E2) except thousand grain weight that showed high heritabilitybut moderate genetic advance. In contrast, in the area of plains (E3), all the traits exhibited high heritability coupled withhigh genetic advance. Since, majority of the traits have shown high heritability with high genetic advance, selection mightbe effective in these traits irrespective of the environment.

Genetic variability and association analysis in the segregating population of extra early barnyard millet [Echinochloa frumentaceae (Roxb.) Link] involved crosses

An investigation was conducted to evaluate the F2 population of two crosses of barnyard millet viz., cross I, ACM-15-343 X IEC 82 and cross II, Co (Kv) 2 X IEC 107 for extra earliness. Genetic variability and association analyses were carried out for sixteen biometrical traits. In both the crosses, high PCV and GCV was observed for the width of flag leaf, length of a lower raceme, number of racemes and grain yield per plant. Low PCV and GCV was observed for days to maturity. The minimum difference between PCV and GCV was observed for all the traits in both crosses, indicating the negligible effect of environment on the expression of the characters. Moderate to high heritability with moderate to high genetic advance in all the traits revealed the predominance of additive gene action. A positive significant correlation was noted for grain yield with plant height, days to flowering, days to maturity, the number and length of nodes, the number of basal tillers, stem diameter and single ear head weight. Path analysis disclosed a high positive direct effect of the number of basal tillers and single ear head weight on yield. These results together help in the selection of superior segregants based on the number of basal tillers and single ear head weight in forwarding them to successive generations. Key words: Barnyard millet, F2, Variability, Association analysis

Effect of Selected Weed Management Practices on the Growth and Yield Components of Finger Millet (Eleusine coracana) in Western Region of Kenya

Finger millet (Elusine coracana) accounts for 8% of the total area and 11% of the millet production worldwide. It is grown on over 4 million ha globally, mainly for food purposes. Millions of people in the dry lands of Central and East Africa, and South of India depend on finger millet as an important source of food to them (CGIAR, 2001). Finger millet is one of the most neglected and underutilized crops. Additionally, the crop has received limited research attention compared to wheat, rice, and maize (FAO, 2011). Therefore, production challenges such as those caused by weeds like goose grass Elusine indica remain at large. Manual weeding is the commonly employed weed control method in finger millet production, but is expensive and labour intensive. The current study was set to evaluate the influence of weed management practices on finger millet growth and yield components. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replicates. The plots measured 2 by 2m with a border width of 1m. The treatments included Pendimethalin, Dimethyl amine, Metolachlor, Metribuzin, Atrazine (at three rates each 1.0, 1.5 and 2.0 l/ha), No weeding and Hand weeding. Data was collected on the number of weed species, weed biomass, number of basal tillers, herbicide phytotoxicity, weed and crop heights, number of panicles, weight of panicles, weight of un-threshed and threshed grains and 1000 grain weight. Data was analyzed using one-way ANOVA using GenStat version 15.1. Application of Pendimethalin at 1.5 and 2.0 L/ha Active Ingredient (AI), resulted in weed optimal control and least phytotoxicity. Results also indicated that the height of finger millet was significantly (p<0.001) higher where the herbicides were applied. Lower weed biomass was also positively correlated with higher crop height, more panicles, high unthreshed and threshed weights and a 1000 grain weight. Application of 2,4D at rates of 1.5L and 2.0L resulted in significantly taller plants 33.00 cm, than the other weed management methods. Finger millet under Pendimethalin 1.5 L gave the highest number of 86 panicles while Atrazine 2.0L and Pendimethalin1.5L methods of weed control, had significantly higher weight compared to all the other treatments. The 1000 seed mass across the treatments averaged 2.31 g while the on the untreated treatments had an average of 1.54 g. Weed control using pre emergence herbicides significantly (p<0.001) increased the yields of finger millet.

Decreasing Defoliation Frequency Enhances Bromus valdivianus Phil. Growth under Low Soil Water Levels and Interspecific Competition

Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.

Evaluation of the Agronomic Traits of 80 Accessions of Proso Millet (Panicum miliaceum L.) under Mediterranean Pedoclimatic Conditions

The continuous increase in the world population and the associated food demands in the wake of climate change are pushing for the development and cultivation of climate-resilient crops that are able to efficiently use natural resources. Proso millet (Panicum miliaceum L.) might be a promising candidate crop thanks to its heat stress resistance and its limited water demand. To date, one of the most important strategies to increase grain yield and to improve other agronomic important traits is through an efficient breeding program based on a wide genetic variability of parental germplasm. In this study, we evaluated the agronomical traits of a world collection of 80 P. miliaceum accessions. The entire collection was evaluated over a 2 year field experiment under Mediterranean pedoclimatic conditions, which exhibited a wide range of variability for plant height (25–111 cm), grain yield (842–3125 kg ha−1), total dry biomass (2767–10,627 kg ha−1), harvest index (HI; 0.25–0.35), Growing Degree Days (GDDs; 581–899), and days to maturity (80–111 d). A non-parametric multivariate analysis of variance (Np-MANOVA) analysis indicated that GDDs to flowering, grain yield, total dry biomass, days to maturity, plant height, and seed yield per plant were useful parameters to differentiate the germplasm accessions. High heritability (>0.60) was observed in both years for plant height, leaf number, basal tiller, seed yield per plant, 100-seed weight, GDDs to flowering, and days to maturity. Grain yield, total dry biomass, and HI reported moderate heritability (0.30–0.60). The findings reported in the present study may provide valuable information that could support researchers in breeding programs to develop high grain-yielding accessions.