Triticale Cultivars Research Articles

The optimization of grain crops’ phytosanitary condition with the associative rhizobacteria application

The effectiveness of the associative rhizobacteria influence on the intensity of the soft wheat and triticale diseases’ development was studied. According to the experimental scheme, seeds were soaked and plants were sprayed twice with a working fluid, containing rhizobacteria strains of Bacillus subtilis 124-11, Sphingomonas sp. K1B and Pseudomonas fluorescens SPB2137 (titer 108-109 cl/ml), and other variants with combined treatment with a liquid organomineral composition Batr Gum were used. In the control plants were treated with water and Batr Gum (by 10 ml/l of water). The biopreparations influence on the diseases development was investigated using generally accepted accounting scales and additional phytopathological indicators. The Bacillus subtilis strain 124-11, had the maximal effectiveness against yellow and brown rust of wheat, and Sphingomonas sp. K1B - against triticale rusts. In particular, the treatment of the local cultivar Leningradskaya 6 with Bacillus subtilis 124-11 led to a decrease in the development of yellow rust by 12 %, the pustules number by 47 %, the strip length by 41 %, the pustule area by 39 %; the brown rust development by 9 %, the pustules number by 50 %, the pustule area the by 40 %. After the Dua, k-828 cultivar treatment with the Sphingomonas sp. K1B strain, a decrease in the plants affection by brown rust was observed by 13 %, the pustules number decreased by 59 %, the pustule area by 52 %. A significant decrease in the powdery mildew development on soft wheat and a decrease in the number of spots with plaque were recorded when using the Sphingomonas sp. K1B strain on cultivars: Leningradskaya 6 - by 12 % (79.4 %), Ajeeba - 19 % (72.5 %), Trizo - 13 % (87.2 %), Sudarynya - 3 % (60 %). On the soft wheat cultivar Sudarynya and triticale cultivars Aist Kharkovskiy and Dua, a decrease in helminthosporiotic root rot was revealed when using associative rhizobacteria; the maximal decrease in the disease development (by 32 %) was noted when using the strain Sphingomonas sp. K1B. When bacterial strains were used combined with the organomineral fertilizer Batr Gum, the development of powdery mildew and yellow rust was much slower than when they were used separately, while the greatest effectiveness against these diseases (by 31 % and 91 %) was revealed in the «Batr Gum + Pseudomonas fluorescens SPB2137» experimental variant.

Correction: Triticale cultivars and seeding rates affect wheat stem sawfly survivorship and parasitism by Bracon cephi

Correction: Triticale cultivars and seeding rates affect wheat stem sawfly survivorship and parasitism by <i>Bracon cephi</i>

Agronomic feasibility of wheat and triticale cultivars in the semiarid of Minas Gerais State, Brazil

The production of winter cereals is becoming increasingly important in Brazil, largely due to advanced techniques that enable considerable qualitative and quantitative gains. This is due to plant breeding under different soil and climate conditions combined with proper management. The present study aims to assess the agronomic feasibility of growing wheat and triticale cultivars with two sowing times in the semiarid region of northern Minas Gerais State, Brazil. The experiment was conducted in 2018 at the Instituto de Ciências Agrárias (Institute of Agricultural Sciences) of Universidade Federal de Minas Gerais, Montes Claros campus. A randomized block design was used, with four replications and an 8 × 2 factorial arrangement consisting of eight genotypes (six wheat and two triticale cultivars) and two sowing times (April 21 and May 12, 2018). The irrigated production of wheat and triticale was agronomically feasible in the semi-arid region of Minas Gerais state and sowing time affected the main agronomic traits of interest of winter cereals. However, it is essential to study the economic feasibility of the crop. Sowing in April was the most indicated for wheat and triticale, with IPR Potyporã, IPR 144 and IPR 111 as the recommended cultivars.

Novel Tetraploid Triticale (Einkorn Wheat × Rye)-A Source of Stem Rust Resistance.

Among cereals, triticale (×Trititcoseale Wittmack ex A. Camus) represents a number of advantages such as high grain yield even in marginal environments, tolerance to drought, cold and acid soils, as well as lower production costs. Together with high biomass of grain and straw, triticale is also considered as an industrial energy crop. As an artificial hybrid, it has not evolved naturally, which is reflected in narrow genetic diversity causing a resistance collapse in recent years. Here, we describe a novel, synthetic tetraploid triticale, which was developed by the crossing of rye (Secale cereale L.) with einkorn wheat (Triticum monococcum spp. monococcum), which possess Sr35 stem rust resistance gene. Three subsequent generations of alloploids were obtained by chromosome doubling followed by self-pollination. The cytogenetic analyses revealed that the amphiploids possess a set of 28 chromosomes (14 of Am-genome and 14 of R-genome). The values of the most important yield-shaping traits for these tetraploid triticale form, including thousand-grain weight, plant height and stem length were higher compared to parental genotypes, as well as standard hexaploid triticale cultivars. This study shows that this tetraploid triticale genetic stock can be an interesting pre-breeding germplasm for triticale improvement or can be developed as a new alternative crop.

Yield of winter triticale cultivars in soil and climatic conditions of the Wielkopolska region in Poland

Since Poland has joined the structures of the European Union (EU), legal regulations at the EU level allow marketing of plant varieties registered in any country of the community. As part of the Post Registration Variety Trials (PRVT) in the Wielkopolska (Greater Poland) voivodeship, the analysis of the interaction of winter triticale cultivars for: height, lodging, diseases, yield and thousand kernel weight in growing seasons 2017–2019 was performed. For farmers, the most important and valuable effect of the research conducted in the PRVT system is the annual “List of varieties recommended for cultivation in the voivodeship”. The main purpose of PRVT research is to help farmers in accurate selection/choice of the most valuable varieties for cultivation, adapted to local conditions. This type of research provides users with continuous information about the variety value for cultivation and use, including their reaction to various agrotechnical factors.

Promising source material for winter triticale breeding under the conditions of the Middle Urals

Background. The northern border of cereal crop cultivation passes through the territory of Sverdlovsk Province. Cultivars of winter triticale developed in the regions of Russia located to the south are grown there, but they die under unfavorable winter conditions. The breeding of this crop in local climate is at an early stage, so a study of source material for breeding new highyielding cultivars adapted to local conditions seems quite pertinent.Materials and methods. In 2017–2020, the Ural Research Institute of Agriculture in Yekaterinburg conducted a study of 78 winter triticale genotypes from 10 regions of Russia and 7 foreign countries. The seeds were obtained from the VIR genebank and breeding centers of Russia. Sowing was carried out in clean fallow on August 20–25 on 1 m2 plots in 3-4 repetitions, with the reference ‘Bashkirskaya korotkostebelnaya’ sown on every 10th plot. Plants were assessed for winter hardiness, yield, density of productive stems, plant height, ear length, number of spikelets and grains per ear, weight of 1000 grains, and ear productivity in accordance with published guidelines.Results. Cvs. ‘Privada’, ‘Tsekad 90’ and ‘Nemchinovsky 58’ combined high winter hardiness (70–81%) with resistance to damage by snow mold (15–20%), high density of productive stems (324–425 pcs/m2), and high yield (562–616 g/m2). They had high 1000 grain weight (45.4–49.1 g) and ear productivity (2.63–2.68 g). High yield (571–670 g/m2) and density of productive stems (285–436 pcs/m2 ) with reduced winter hardiness (62–72%) and resistance to snow mold (30–35%) was observed in cvs. ‘Sirs 57’, ‘Sotnik’, ‘Germes’, ‘Antey’, ‘Beta’, ‘Don’, and lines 1/1 and 8003 from Sweden.

Compensatory Effect of the ScGrf3-2R Gene in Semi-Dwarf Spring Triticale (x Triticosecale Wittmack).

The dwarfness in many triticale cultivars is provided by the dominant Ddw1 (Dominant dwarf 1) allele found in rye. However, along with conferring semi-dwarf phenotype to improve resistance to lodging, this gene also reduces grain size and weight and delays heading and flowering. Grf (Growth-regulating factors) genes are plant-specific transcription factors that regulate plant growth, including stem growth, in terms of length and thickness, and leaf and fruit size. In this work, we partially sequenced the rye gene ScGrf3 on chromosome 2R homologous to the wheat Grf3 gene, and found multiple polymorphisms in intron 3 and exon 4 complying with two alternative alleles (haplotypes ScGrf3-2Ra and ScGrf3-2Rb). For the identification of these, we developed a codominant PCR marker. Using a new marker, we studied the effect of ScGrf3-2R alleles in combination with the Ddw1 dwarf gene on economically valuable traits in F4 and F5 recombinant lines of spring triticale from the hybrid combination Valentin 90 x Dublet, grown in the Non-Chernozem zone for 2 years. Allele ScGrf3-2Ra was associated with greater thousand-grain weight, higher spike productivity, and earlier heading and flowering, which makes ScGrf3-2R a perspective compensator for negative effects of Ddw1 on these traits and increases prospects for its involvement in breeding semi-dwarf cultivars of triticale.

Managing the quality of seeds from cereal conditioned with effective microorganisms (EM) and red light (RL)

The study pertained to environmentally-friendly methods in the cultivation of cereal, and aimed to manage the quality of rye and triticale seeds and determine the impact of seed conditioning using effective microorganisms (EM), red light (RL), and a combination of the two (RL × EM) on the yield of grain and straw. Moreover, the seeds were sown into soil with and without EM conditioning, designated as 0 and PEM. The yield fluctuations depended mostly on the studied rye and triticale cultivars. The best effects we observed in soil without EM conditioning for Dańkowskie Złote rye and Moderato triticale. The increase in grain and straw yields was, respectively: 26% (RL), 31% (RL × EM), 40% (EM), and 17% (RL × EM), 23% (RL), 32% (EM) – Dańkowskie Złote, 27% (RL × EM), 44% (EM), 46% (RL), and 17% (RL × EM), 51% (EM), 78% (RL) – Moderato. In turn, seeds exposed to the experimental treatment and sown into soil containing EM produced reduced yields in both of the above cultivars. It is noteworthy that the conditioning methods employed in the field experiment can facilitate increased yields but most importantly contribute to the resilience of agrosystems and can therefore have environmental benefits. It is noteworthy that the conditioning methods employed in the field experiment can facilitate increased yields but most importantly contribute to the resilience of agrosystems and can therefore have environmental benefits.

Winter Cereal Reactions to Common Root Rot and Crown Rot Pathogens in the Field

In Australia, Fusarium pseudograminearum and F. culmorum are the two main fungi causing crown rot, while Bipolaris sorokiniana is the causal agent of common root rot. Fusarium graminearum is typically linked with Fusarium head blight; however, it has been associated with crown rot in Australia and other parts of the world. This study investigated the reactions of single cultivars of barley, bread wheat, durum wheat, oat, and triticale to inoculation with strains of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana in field trials across two seasons. Fusarium pseudograminearum and F. culmorum caused greater visual discolouration than F. graminearum and B. sorokiniana on both stems and sub crown internodes of all hosts. Fusarum pseudograminearum caused the greatest reduction in plant dry weight across hosts in both years. Durum wheat (cv. Hyperno) barley (cv. Grimmett), bread wheat (cv. Livingston) and triticale (cv. Endeavour) observed significantly high levels of visual discolouration on stems when inoculated with F. pseudograminearum, while oat (cv. Genie) exhibited the least visual discolouration. Despite variation in the visual discolouration, the DNA of all pathogens were detected in all cultivars. This research further highlights the complicated nature of the pathogen × strain × cultivar × environment interaction, which remains a challenge in breeding for genetic resistance. The specific infection of each fungus and the host responses in these field trials improves our understanding of disease development and its importance in cropping systems.

Promising cultivars of winter triticale for grain production in the north-west of the Astrakhan region

Triticale, due to its specific properties to form stable grain yields in the zones with risky agriculture, should find wider application in acutely arid conditions. Therefore, the use of highly productive cultivars of winter triticale in semi-desert zone of the north-west of the Astrakhan region is relevant. The aim of the research was a comprehensive assessment of promising winter triticale cultivars of different ecological and geographical origin for adaptability to stressful meteorological factors in semi-desert zone of the northwestern Astrakhan region. To determine the main indicators of adaptability (winter hardiness, plasticity, stability, stress tolerance, genetic flexibility), six promising winter triticale cultivars (Tribun, Interes, PRAG 152, Khleborob, Zhnets and Uragan) were studied. Field agroecological tests were conducted on rainfed fields of Precaspian Agrarian Federal Scientific Center of the RAS with different moisture level in 2018-2020. Nelli cultivar was used as a control. The methods of Selyaninov G.T., Zhivotkov L.A., Eberhart S.A., and Rassell W.A. were used for calculations. During periods of active vegetation of winter triticale, Selyaninov hydrothermal coefficient varied from 0.3 to 0.5 (zone of strong and very strong drought); environment index was from -0.67 to 0.66. According to the data obtained, cv. Khleborob showed the greatest adaptive potential and consistently high yield under various meteorological conditions of the season compared to the other tested winter triticale varieties. Moreover, the cultivar had good winter hardiness (5 points) and survival (90.8 %). On the average for the years of research it showed high adaptability coefficient (1.43), and the indicators of its plasticity and genetic flexibility were 0.77 and 1.40, respectively. Therefore, cv. Khleborob can be recommended for use in the acutely arid conditions in semi-desert zone of the northwestern part of the Astrakhan region.

Pyramiding wheat pre-harvest sprouting resistance genes in triticale breeding

Pre-harvest sprouting (PHS) is an important problem in cereal production reducing yield and grain quality. After decades of improvement, triticale remains particularly susceptible to PHS but no resistance genes or QTLs were identified so far in this species. As wheat shares the A and B genomes with triticale, wheat PHS resistance genes can be introgressed into triticale genome by recombination after interspecific crosses. In this project, three PHS resistance genes have been transferred from wheat to triticale by marker-assisted interspecific crosses, followed by four backcrosses. The gene TaPHS1 from the 3AS chromosome of cultivar Zenkoujikomugi (Zen) and the TaMKK3 and TaQsd1, respectively located on the 4AL and 5BL chromosomes derived both from cultivar Aus1408, were pyramided in the triticale cultivar Cosinus. Only the TaPHS1 gene increases consistently the PHS resistance in triticale. The lack of efficacy of the other two genes, especially TaQsd1, could be the result of an imperfect linkage between the marker and the gene of interest. The introduction of PHS resistance genes did not alter agronomic nor disease resistance performances of triticale. This approach leads to two new, agronomically performant and PHS-resistant triticale cultivars. Today, two breeding triticale lines are ready to enter the official registration process.

Quantitative-Genetic Evaluation of Resistances to Five Fungal Diseases in A Large Triticale Diversity Panel (×Triticosecale)

The man-made cereal triticale was fully resistant to the biotrophic diseases powdery mildew, leaf rust, yellow rust, and stem rust from its introduction in Europe in the mid-1970s until about 1990. In the following years, new races that were able to infect at least some triticale genotypes developed in all four pathogen populations, and resistance breeding came into focus. Here, we analyzed 656 winter triticale cultivars from 12 countries for resistance to these biotrophic diseases and Fusarium head blight (FHB) at up to 8 location-year combinations (environments). FHB ratings were corrected for plant height and heading stage by comparing three statistical methods. Significant (p &lt; 0.001) genetic variances were found for all resistances with moderate to high entry-mean heritabilities. All traits showed a normal distribution, with the exception of stem rust, where the ratings were skewed towards resistance. There were no substantial correlations among the five disease resistances (r = −0.04 to 0.26). However, several genotypes were detected with multi-disease resistance with a disease rating below average for all five diseases simultaneously. In future, such genotypes must be selected primarily to cope with future challenges of less pesticide use and global climate change.

Triticale cultivars and seeding rates affect wheat stem sawfly survivorship and parasitism by Bracon cephi

Several insects, including the wheat stem sawfly ( Cephus cinctus Norton, Hymenoptera: Cephidae), interfere with biomass and grain production of triticale (× Triticosecale). We conducted a 2-year study in southern Alberta to compare the cultivars Pronghorn and AC Ultima at 200 and 400 seeds/m2 in terms of wheat stem sawfly damage and incidence of a parasitoid wasp ( Bracon cephi Gahan, Hymenoptera: Braconidae). Plants of AC Ultima seeded at the high rate were on average less damaged than those of Pronghorn, and had more parasitoids. AC Ultima was characterized by more solid pith development in the lumen, compared with Pronghorn, and it can be considered adequate germplasm for the development of more resistant solid triticale cultivars.

Investigation of the effects of different genotypes on regeneration capacity in Triticale

Triticale (x Triticosecale Wittmack) is a synthetic amphiploid cereal that grows on about 3 million hectares in the world. It is grown mostly for forage or animal feed, although some triticale-based foods can be purchased at health food stores or are found in some breakfast cereals. Mature embryos of two triticale cultivars (Ümran Hanım and Melez 2001) were used as the resources explants. The effects of one auxin type (2,4-D) and three various concentrations, (4.0 mg/l; 8mg/l; 12.0mg/l) callus formation and plant regeneration were determined. Callus formation values were detected over 85% in three concentrations. In terms of results, the highest embryogenic callus formation rate was determined 46.91 % at 12 mg/l of Ümran Hanım dicamba. However, the lowest embryogenic callus formation rate was found with a value of 12.86% in Ümran Hanım's 2,4-D 8.0 mg/l hormone application. The highest regeneration capacity was determined at 12.09% at a dose of 12.0 mg/l of Mikham 2001 2,4-D. However, the lowest regeneration capacity was determined at 2.2% at the dose of 4 mg/l of Ümran Hanım 2,4-D. Our results displayed that auxin type and hormone dosage were very significant on the triticale mature embryos.

A strategy of the new “green revolution” in wheat breeding: celebrating the jubilee of Lyudmila A. Bespalova, Full Member of the Russian Academy of Sciences

On April 2, 2022, the national and international scientific communities who specialize in wheat breeding and agricultural producers in the wheat sector celebrated the birthday jubilee of Acad. Lyudmila A. Bespalova, a renowned breeder and head of the Department of Wheat and Triticale Breeding and Seed Production at the P.P. Lukyanenko National Grain Center.The main result achieved by L.A. Bespalova’s team is more than 170 cultivars of various wheat species and triticale, including over 100 bread wheat cultivars that supply about 10% of worldwide grain harvests of this staple crop, most important for the existence of mankind. The team succeeded in commercializing their competitive wheat cultivars with unique combinations of agronomic traits (grain quality, adaptability to abiotic and biotic stressors, short growing season, etc.) because they developed and implemented a new industrial breeding system, unmatched in the world. In its essence, the approach developed under the leadership of L. A. Bespalova at the P.P. Lukyanenko National Grain Center is a practically proven strategy of the new “green revolution” capable of ensuring the global food security.

Microscopic and Physiological Analysis of Somatic Embryos Under in Vitro Culture in Triticale

Somatic embryogenesis is a developmental process during which plant somatic cells, under in vitro conditions, produce embryogenic cells that develop into somatic embryos. Somatic embryogenesis is an efficient method clonal propagation in vitro of plants. Mature embryos were used as explant source for embryogenic callus formation and the callus produced compact, healthy and most mature embryos were induced embryogenic callus. Somatic embryos showed a similar morphologically to their non-somatic counterparts in their development. In a comparative study, total protein, DNSA and activities of some antioxidant enzymes including H2O2, MDA of somatic embryos of three triticale cultivar ‘Tatlıcak, Alper Bey and Mikham’ at embryogenic callus stages were analyzed. However; somatic embryos displayed the highest level of DNSA, MDA, H2O2 and total protein in all tested cultivars. Our results showed that the triticale somatic embryo maturation process was complete within two years in vitro conditions.

Сучасна селекція високоврожайних сортів тритикале з поліпшеною якістю зерна

Goal. To study genotypes of hexaploid triticale using systematic ecological tests in contrast conditions and create new medium and low-stem lines with high potential productivity and improved grain quality, form multi-line varieties with the straw length of 80 – 120 cm, the yield of 9.5 – 13.5 t/ha, high quality of gluten, dough and bread. Methods. The object of research was: samples of winter and spring triticale, soft and durum wheat, rye of different geographical and genetic origins, intergeneric, interspecific and intraspecific hybrids, as well as populations created on their basis. The sowing rate was 4.5 million similar seeds per 1 hectare, the plot area was 10 m2. Intraspecific hybridization was used in winter triticale breeding with the assessment of grain and bread quality of multilinear varieties. Hybrid populations were created by crossing hexaploid triticales, which differed in origin and type of development. Results. The use of the method of intraspecific hybridization in combination with long-term trials of hybrid populations and lines in contrast conditions allowed the creation of new varieties of winter triticale. Research work was carried out on the creation of triticale cultivars of a fundamentally new type, which differ in the areas of use, are short-stemmed and high-quality grain. Triticale varieties created in recent years in research institutions of the NAAS had high productivity potential, comprehensive immunity to major diseases, and a large volume of bread without improvers (800 ml) with a total baking score of 9 points. Conclusions. Genotypes of hexaploid triticale were studied using systematic ecological tests in contrast conditions, and new medium and low stem lines with high potential productivity and improved grain quality were created, multilinear varieties were formed with a straw length of 80 – 120 cm, a yield of 9.5 – 13.5 t/ha, high-quality gluten, dough and bread.

Genotyping-by-sequencing and genome-wide association study reveal genetic diversity and loci controlling agronomic traits in triticale.

The genetic diversity and loci underlying agronomic traits were analyzed by the reads coverage and genome-wide association study based genotyping-by-sequencing in a diverse population consisting of 199 accessions. Triticale (× Triticosecale Wittmack) is an economically important grain forage and energy crop planted worldwide for its high biomass. Little is known about the genetic diversity and loci underlying agronomic traits in triticale. We performed genotyping-by-sequencing of 199 cultivars and mapped reads to the A, B, D, and R genomes for karyotype analysis. These cultivars could mostly be grouped into five types. Some chromosome abnormalities occurred with high frequency, such as 2D (2R) substitution, deletion of the long arm of chromosome 2D or the short arm of 5R, and translocation of the long arms of 7D/7A, the short arms of 6D/6A, or the long arms of 1D/1A. We chose only widely planted hexaploid triticale cultivars (153) for genome-wide association study. These cultivars could be divided into nine distinct groups, and the linkage disequilibrium decay was 25.4kb in this population. We identified 253 significant marker-trait associations (MTAs) on 20 chromosomes, except 7R. Twenty-one reliable MTAs were identified repeatedly over two environments. We predicted 16 putative candidate genes involved in plant growth and development using the genome sequences of wheat and rye. These results provide a basis for understanding the genetic mechanisms of agronomic traits and will benefit the breeding of improved hexaploid triticale.

Effects of harvest date and growth stage on triticale forages in the southwest USA: kinetics of in vitro disappearance of fiber and dry matter.

Recently, there has been interest in including triticale (X Triticosecale Wittmack) within forage programs in the southwest USA. Our objectives were to evaluate in vitro disappearance kinetics of neutral detergent fiber (NDF) and dry matter (DM) for cultivars identified during 2019 as positively or negatively deviant from typical cultivars, based specifically on regressions of 48-h in vitro disappearance of NDF on growth stage (GRST). All NDF analyses included the use of heat-stable α-amylase and sodium sulfite, as well as correction for residual ash (asNDFom). Seven triticale cultivars were established on December 18, 2019 at the University of Arizona Maricopa Agricultural Center, located near Maricopa, AZ. Forage plots were arranged in a randomized complete block design with three complete blocks (replications), and then harvested on seven dates the following late-winter and spring (February 26, March 17, April 1, April 14, April 28, May 12, and May 26). Based on a linear model, GRST was highly variable among cultivars on March 17 (44 ± 10.6), April 1 (57 ± 12.1), April 14 (67 ± 8.9), and April 28 (79 ± 7.2) compared with other harvest dates (SD ≤ 1.7). For concentrations of asNDFom, all cultivars exhibited linear (P ≤ 0.042) and quadratic (P < 0.001) polynomial contrasts in response to harvest date, and all cultivars except Merlin Max (P ≥ 0.063) exhibited at least one additional cubic or quartic effect (P ≤ 0.015). A contributing factor to the unique response by Merlin Max was the numerically greater maximum canopy height (145 ± 9.8cm) compared with the mean of all cultivars (107 ± 17.7cm), which also was associated with greater percentages of stem, as well as reduced percentages of DM partitioned within the grain head. Regressions of asNDFom disappearance after 30- or 48-h incubations on GRST indicated this was an effective independent variable (R2 ≥ 0.927), and responses were most often linear in nature. Generally, relationships for DM disappearance were quadratic, ostensibly due to the complicating effect of grain fill, but GRST was again an effective predictor variable with R2 statistics ≥ 0.852 for 12 of 14 combinations of cultivar and incubation time. Predicted percentages of digestible DM attributed to asNDFom disappearance were ≥50.3% through the fully flowered stage of growth, but digestible contributions from nonfiber components following the onset of grain fill profoundly affected overall DM digestibility among cultivars harvested at later GRST.

Effects of harvest date and growth stage on triticale forages in the southwest United States: agronomic characteristics, nutritive value, energy density, and in vitro disappearance of dry matter and fiber.

Recently, there has been increased interest in including triticale (X Triticosecale Wittmack) or other winter cereals within forage programs throughout the southwest United States. Our objectives were to screen 14 diverse triticale cultivars for agronomic and nutritive characteristics with specific emphasis on identifying normal, as well as deviant, responses to the calendar date and plant maturity for forages seeded in December and harvested from late February throughout May at Maricopa, AZ. Fourteen cultivars were established in a randomized complete block design with each cultivar represented within each of three field blocks. Plots were clean tilled and established on December 18, 2018, and then harvested at 2-wk intervals beginning on February 27 and ending May 23, 2019. Across all harvest dates, forage (N = 315) energy density (NEL) exhibited strong negative correlations with growth stage (r = -0.879), plant height (r = -0.913), head weight (r = -0.814), and estimated dry matter (DM) yield (r = -0.886) but was positively associated with percentages of leaf (r = 0.949), and weakly associated with percentages of the stem (r = 0.138). Through April 10, similar correlations were observed within individual harvest dates (N = 45) for growth stage, leaf percentage, and plant height but not for stem or head-weight percentages. Within later harvest dates, only sporadic correlations with NEL were observed. Primarily cubic regression relationships for neutral detergent fiber, acid detergent lignin, 30- and 48-h in vitro disappearance of DM and fiber, and NEL were fit for the mean or typical cultivar using both days from February 1 and growth stage as independent variables. Coefficients of determination (R2 ≥ 0.860) in all cases indicated a good fit for the polynomial models. For NEL, deviation from the typical cultivar when days from February 1 was used as the independent regression variable was largely affected by cultivar maturation rate. When the growth stage was substituted as the independent variable, plant height, stem percentage beginning at anthesis, and low grain-head percentage were associated with the maximum negative deviant cultivar (Merlin Max). The 0.23 Mcal/kg difference between maximum positive and negative deviant cultivars at a common late-boot/early-heading stage of growth suggests that some attention should be placed on cultivar selection as well as forage inventory needs and overall cropping goals.