Plant Lodging Resistance Research Articles

Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen (N), phosphorus (P), and potassium (K) uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development, increased nutrient accumulation, and increased yield. Compared with conventional soil management (CK), root length, root surface area, and root dry weight at 0–80cm soil depth under subsoil tillage to 30cm (T1) and subsoil tillage to 50cm (T2) were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2>T1>CK at the 12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50cm, a characteristic that favors a high and stable yield under extreme environments.

내한 다수성 추파 조사료용 총체 귀리 신품종 '다한'

'다한'은 추위에 강해 충청지역에서도 월동이 가능하면서 수량이 많은 귀리 품종 개발을 목표로 2011년 농촌진흥청 국립식량과학원에서 육성되었다. 잡종은 1999년에 Sprinter/73625의 <TEX>$F_1$</TEX>을 모본, 귀리26호를 부본으로 인공교배하여 작성되었으며, 집단 및 계통 선발에 의해 내한성이 강하고 초형이 우수한 'SO99027-GB-B-113-4-4-3' 계통을 선발하였다. 이 계통은 2005년부터 2008년까지 4개년에 걸쳐 생산력검정시험을 실시하였으며, 내한성이 강하고 수량이 많아 '귀리75호'로 계통 이름을 부여하고 2009년부터 2011년까지 3년간 충남 예산, 전북 김제와 익산, 제주 등 4개 지역에서 지역적응시험을 실시하였다. 이 계통은 2011년 11월 신품종으로 선정되었으며, 그 특성은 다음과 같다. 귀리 신품종 '다한'은 중간 크기의 농록색 잎, 황백색 줄기, 황갈색의 종실을 가졌다. 출수기는 전국 평균 5월 13일로 표준품종인 '삼한'과 비슷하였으며, 내한성은 '삼한'과 대등하였고, 도복에 강하였다. 건물수량은 ha당 평균 15.6톤으로 14.1톤인 '삼한'에 비해 11% 많았다. '다한'의 조단백질 함량은 8.4 %로 '삼한'의 9.9 %에 비해 다소 낮았으나 TDN은 60.8 %, TDN 수량은 ha당 9.5톤으로 59.3 %와 8.4톤인 '삼한'보다 높았다. '다한'의 적응지역은 1월 최저평균기온이 <TEX>$-7^{\circ}C$</TEX> 이상인 지역이면 전국 어느 곳에서나 재배가 가능하다. 'Dahan' (Avena sativa L.), a winter oat cultivar for forage use, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, National Institute Crop Science (NICS), Rural Development Administration (RDA) in 2011. It was derived from an original cross between <TEX>$F_1$</TEX>[Sprinter/73625] and 'Gwiri26'. Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Suwon. A line, 'SO99027-GB-B-113-4-4-3', was selected for cold tolerance and good agronomic characteristics and as a line name of 'Gwiri75'. The line 'Gwiri75' was subsequently evaluated for cold tolerance and forage yield during 3 years in four region such as Yesan, Iksan, Kimjae, and Jeju, from 2009 to 2011 and finally named as 'Dahan'. Though similar in heading date to the check cultivar Samhan, 'Dahan' had tall plant length and lodging resistance. It's average forage dry matter yield harvested at milk-ripe stage was 15.6 ton <TEX>$ha^{-1}$</TEX>, compared with 14.1 ton <TEX>$ha^{-1}$</TEX> of check cultivar. Cultivar 'Dahan' was lower to the check cultivar 'Samhan' in protein content (8.4% and 9.9%, respectively), while it was superior to the check cultivar in total digestible nutrients (TDN) (60.8% and 59.3%, respectively), and in TDN yield <TEX>$ha^{-1}$</TEX> (9.5 ton and 8.4 ton, respectively). Fall sowing of 'Dahan' is recommended only in the areas where daily minimum mean temperatures are averaged higher than <TEX>$-7^{\circ}C$</TEX> in January, and excluded in mountain area where frost damage is presumable.

Integration and “Overview” analysis of QTLs related to plant height in soybean

Plant height, one of the most important factors for plant architectures, is closely related with some important traits such as plant density, lodging resistance and yields.. In the present study, 201 QTLs related to plant height of soybean from database and references were analyzed. The results revealed that 15 consensus QTLs located on chromosomes 6, 7, 11, 13, and 18 were identified after physical integrations and Meta analysis using the software BioMercator 2.1. Moreover, "Overview" method was used to optimize these QTLs based on statistic analysis. Some of the valid QTL regions were narrowed down to the 0.1 cM and mapped on certain chromosomes. Furthermore, the functions of all genes located in these confidence regions were predicted and 17 candidate genes that might be related to plant height were identified. These results would lay a foundation for fine mapping of QTLs related to plant height and marker-assisted breeding in soybean.

QTL mapping of stalk bending strength in a recombinant inbred line maize population

Stalk bending strength (SBS) is a reliable indicator for evaluating stalk lodging resistance of maize plants. Based on biomechanical considerations, the maximum load exerted to breaking (F max), the breaking moment (M max) and critical stress (σ max) are three important parameters to characterize SBS. We investigated the genetic architecture of SBS by phenotyping F max, M max and σ max of the fourth internode of maize plants in a population of 216 recombinant inbred lines derived from the cross B73×Ce03005 evaluated in four environments. Heritability of F max, M max and σ max was 0.81, 0.79 and 0.75, respectively. F max and σ max were positively correlated with several other stalk characters. By using a linkage map with 129 SSR markers, we detected two, three and two quantitative trait loci (QTL) explaining 22.4, 26.1 and 17.2% of the genotypic variance for F max, M max and σ max, respectively. The QTL for F max, M max and σ max located in adjacent bins 5.02 and 5.03 as well as in bin 10.04 for F max were detected with high frequencies in cross-validation. As our QTL mapping results suggested a complex polygenic inheritance for SBS-related traits, we also evaluated the prediction accuracy of two genomic prediction methods (GBLUP and BayesB). In general, we found that both explained considerably higher proportions of the genetic variance than the values obtained in QTL mapping with cross-validation. Nevertheless, the identified QTL regions could be used as a starting point for fine mapping and gene cloning.

Morphological and yield responses of winter wheat (Triticum aestivum L.) to raised bed planting in Northern China

Six winter wheat (Triticum aestivum L.) varieties (Jimai 19, Jimai 20, Jimai 21, Yannong 19, Jining 12 and Jining 16) were grown in 8 crop seasons/site combinations to investigate the effect of raised bed planting as compared to the conventional flat planting on wheat plant morphology, grain yield and associated yield components in Northern China. Raised bed planting produced a more ideal plant structure composed of larger basal leaves with smaller top leaves. Crop canopy analysis indicated that raised bed planting produced more durable dry matter weight of green leaves from the top of the canopy to the bottom as compared to conventional flat planting. In addition, raised bed planting shortened the basal first and second internodes and reduced plant height, leading to less crop lodging when compared with conventional flat planting. Under bed planting, the spike number per unit area was decreased, but the number of grains per spike and the 1000-grain weight of wheat were significantly increased in comparison with flat planting. Ultimately, raised bed planting produced more grain yield than flat planting through the integrative effect of these yield components. It is concluded that raised bed planting can optimize wheat morphological traits, enhance plant lodging resistance, and thereby increase the wheat productivity and yield difference between two planting systems varied from 6.6 to 12% over 5 locations in favour of raised bed planting. Key words: Winter wheat, conventional flat planting, raised bed planting, plant morphology, grain yield.

Genótipos de trigo: características agronômicas em dois locais do estado de São Paulo

A obtenção de cultivares com características agronômicas de interesse tem resultado em significativos incrementos na produção de grãos. Dezoito linhagens de trigo e duas cultivares-controle (IAC-24 e IAC-370) foram avaliadas quanto à produção de grãos, altura das plantas, ao acamamento, comprimento da espiga e aos componentes de produção, em experimentos instalados em Capão Bonito (condições de sequeiro e solo ácido) e Tatuí (condições de irrigação por aspersão e solo corrigido), em 2005 e 2006. Os genótipos também foram avaliados quanto à tolerância à toxicidade de alumínio, em soluções nutritivas. A linhagem 7 (VEE"S"/RL6020/2*YR/3/VEE"S" /4/CEP8236/5/BR15/CEP88113/6/IAC-24) se destacou para produção de grãos, em Capão Bonito e a cultivar IAC-370 e as linhagens 14 (CMH81.38/2*KAUZ//ATTILA), 16 (BARBET1), 17 (MILVUS2), 18 (KASORO1), 19 (BAV92*2/TSC//BABAX) e 20 (PEWIT1), em Tatuí. Constituíram-se em linhagens de interesse ao programa de melhoramento: nos dois locais a 13 (CROC-1//Aegilops squarrosa(205)//KAUZ/3/ATTILA) pelo porte semianão mais baixo e pela resistência ao acamamento; e as 5 (CEP8435/CEP17//BR23/3/IAC-24), 17 e 18 pelos grãos pesados; a 8 (KITE/PAPAGO//IAC-24) e 10 (HUAYUNINIA/IAC-231), em Capão Bonito e a 19, em Tatuí, pelas espigas compridas, maior número de espiguetas e de grãos por espiga. Nos genótipos mais produtivos, a tendência foi as plantas mais altas, com espigas mais compridas, maior número de grãos e de espiguetas, em Capão Bonito e as espigas mais compridas e os grãos mais pesados, em Tatuí. Nas linhagens 3 (KLATY//CNO"S"/GLL/3/NPO/CDL/BB"S"/CNO"S"/CNO/3/ IAC-24), 4 (BR35/BR14//IAC-24), 5, 6 (KITE/PAPAGO//IAC-24), 7 (VEE"S"/RL6020/2*YR/3/ VEE"S"/4/CEP8236/5/BR15/CEP88113/6/IAC-24), 8, 9 (KEA/BUC//IAC-120), 10, 11 (GCWI/ SERI//DOVE/BUC/3/IAC-24), 17 e 18 houve elevada tolerância à toxicidade de alumínio.

Differential expression of lodging resistance related QTLs in rice ( Oryza sativa L.)

Traits related to plant development and lodging resistance in 292 rice recombinant inbred lines (RILs) were investigated by dissecting QTLs affecting four basal internodal traits of the main stem, lengths of five elongated internodes contributing to plant height (PH), and three traits related to heading date (HD). The RILs showed tremendous transgressive segregation for all the traits and a total of 41 genomic regions associated with one or more measured traits were detected. These included 17 QTL regions affecting one or more basal internodal traits, 21 associated with one or more PH and related traits, and 12 for HD and/or its component traits. Of the 21 genomic regions associated with PH traits, two QTL clusters on chromosomes 6 and 10 were expressed consecutively during rice development, and the remaining 19 QTLs appeared to be expressed at one or more specific developmental stages, revealing an important aspect of the relationship between PH and its component traits. The transition from the vegetative growth to the reproductive stage in rice appeared to have a large effect on QTL expression, reflected by the different behaviors of most QTLs affecting panicle length from other PH QTLs. The 17QTL regions associated with one or more basal internodal traits plus nine QTLs affecting two lower elongated internodes were expected to contribute to lodging resistance (LR) of rice. The large allelic differences at these QTLs between japonica and indica parents imply that improved LR in rice can be readily achieved by combining large numbers of QTL alleles affecting stem length, strength, and thickness in indica/ japonica crosses. Specific expression patterns of the identified QTLs and their contributions to morphological traits related to plant development and LR are expected to provide important information for marker-assisted improvement of the target traits in rice and cloning genes underlying QTL of interest.

Effects of seeding rate and plant density on sclerotinia stem rot incidence in canola

Sclerotinia stem rot (Sclerotinia sclerotiorum Lib. deBary) affects canola wherever it is grown. Seeding rates, which are believed to affect the microclimate beneath the canopy, were evaluated for their impact on sclerotinia stem rot incidence. A study with five seeding rates (2.2 kg/ha, 3.3 kg/ha, 6.7 kg/ha, 13.3 kg/ha and 20.0 kg/ha) and four canola cultivars chosen for their variation in canopy structure and lodging resistance was conducted in Carman, Manitoba, Canada, in 2001 to 2003. A significant relationship between sclerotinia stem rot disease incidence (DI) and seeding rate was found. With an increase in seeding rate, the DI was significantly increased in the mean of the canola cultivars, and individually, only in the lodging-prone cultivar AC Excel. Lodging significantly increased for all cultivars when seeding rates exceeded the standard 6.7 kg/ha. Multiple regression analysis revealed that both plant density and lodging explain the majority of the variation in DI. Both plant density and lodging resistance varied in having a larger influence on DI depending on the year and cultivar analysed. Our results indicate that increasing seeding rate does modify the microenvironment and increases the potential for lodging, which may be responsible for plant-to-plant spread of this disease.

AC Cora hard red spring wheat

AC Cora, hard red spring wheat (Triticum aestivumL.), exhibited high levels of leaf rust resistance and was adapted to the southern Canadian prairies. AC Cora produced significantly more grain yield than Neepawa (6.8%), Columbus (6.5%) and Roblin (7.4%), and slightly more (3.0%) than Katepwa. It matured significantly earlier than Columbus, slightly earlier than Neepawa and Katepwa and slightly later than Roblin. AC Cora was similar in plant height and lodging resistance to Katepwa. AC Cora was eligible for all grades of the Canada Western Red Spring (CWRS) wheat class. Key words: Triticum aestivum L., cultivar description, grain yield, leaf and stem rust

Harohawk common bean

Harohawk black bean bean (Phaseolus vulgaris L) has high yield potential with dull seed coat luster and semi-determinate growth habit with erect plant type and lodging resistance, medium season maturity and is moderately resistant to common bacterial blight. Key words: Phaseolus vulgaris, black bean, cultivar description, plant type, common bacterial blight

방사선 이용 벼 돌연변이 계통 선발 및 농경 형질조사

Radiation technique in agriculture was initiated to develop mutant rice. Seeds of Daechungbyeo rice were irradiated with 250 Gy gamma ray for the purpose of inducing and selecting rice variants. Some quantitative traits of the variants in M generation were evaluated and RAPD analysis was carried out. Variants showed a wider range of agronomic characteristics in both a positive and a negative direction compared with their original variety. The new mutants were characterized by an increased or decreased in plant height, lodging resistance and shorter panicle. RAPD analysis showed that polymorphic bands were presented in most of the primers. In comparison with the original variety, variants were classified into four groups through UPGMA analysis. Among mutants no. 91, 139, 140 and 141 was ranked as salt tolerance and the proline content of these mutants was more increased than that of original variety. The lines of 139, 140 and 141 had the highest genetic distance as compared to original variety in the dendrogram. It is expected that such variants will be useful not only for studying molecular genetics but also for breeding research and genetic analysis.s.

Analysis of the effects of parental genotypes of rye lines on the development of quantitative traits in primary octaploid triticale. Plant height

When breeding the primary spring octoploid triticale derived from crosses of various inbred rye lines to wheat Chinese Spring, the effects of the rye genotype and growth conditions on the plant height and proportion of the first, second, and final (pedicle) internodes to the entire stem length were studied. Two triticale groups were examined: homozygotes for the dominant (Ddw1) and recessive (ddw1) alleles of the gene responsible for short stem in rye. In the short stem triticale lines carrying the Ddw1 alleles, the plants were 20 cm shorter on average than those in the ddw1-carrying lines, and the distribution of the two triticale groups overlapped significantly. In both groups, the lines significantly differing in plant height could be differentiated, because of allelic diversity of the additional genes controlling this trait along with the Ddw gene. In most triticale lines, especially in the Ddw1-carrying ones, the plant height was much reduced under unfavorable growth conditions. At the same time, a short-stem line was isolated, which is characterized by ecological plasticity, like the maternal wheat cultivar. In the triticale studied, the stem structure depended on the short-stem rye genotype. The two-year study showed that in the triticale carrying the dominant allele of this gene, the first internode is significantly extended, whereas the upper (pedicle) internode is reduced, which increases plant lodging resistance. The differences revealed between the rye lines as well as their effect on the quantitative triticale traits are discussed in view of a variant of the hybridological analysis, which had been previously proposed for identification and mapping of the correspondent rye genes.

Morphological Traits Associated with Lodging Resistance of Spring Wheat (Triticum aestivum L.)

Throughout the world, lodging in cereals causes great losses in yield each year. A two year field study was conducted to determine the relationship of morphological traits to lodging resistance in spring wheat (Triticum aestivum L.) breeding lines and to find easily measurable traits related to lodging resistance. A set of 15 breeding lines, representing a wide range of combinations of plant height and lodging resistance, was evaluated.During the first year, 29 morphological traits were measured at two growth stages and correlated with the lodging score. Higher correlations were found for traits measured at anthesis (DC 65) than for traits measured at maturity (DC 92); most of the fresh weight traits correlated better to lodging resistance than did the corresponding dry matter parameters. During the second year the six traits of plant height, stem length, stem diameter, ear weight, stem weight and stem weight per cm were measured at anthesis and correlated with the lodging score.From the pooled data of four experiments, significant correlations between the lodging score and single morphological traits were found for stem diameter and stem weight per cm. Thicker stems and heavier stems (mg per cm) were indicative for better lodging resistance. Stem diameter and stem weight cm−1 explained 48.5 % and 49.7 %, respectively, of the phenotypic variation in lodging resistance. Multiple linear regression equations indicated that 77.2 % of the variation in lodging resistance was based on stem weight cm−1 and on the weight of the ear.

Linhagens diaplóides de trigo: produção de grãos, características agronômicas e tolerância à toxicidade de alumínio

Compararam-se 18 linhagens de trigo diaplóides obtidas via cultura de anteras de plantas híbridas, em geração F1, e os cultivares Al Res 102/84 e IAC-24, em quatro ensaios instalados em condições de irrigação por aspersão e de sequeiro. Analisaram-se a produção de grãos, outros componentes da produção, características agronômicas e resistência à ferrugem-da-folha. Estudou-se também a tolerância ao alumínio em soluções nutritivas, em condição de laboratório. A linhagem diaplóide 5, provinda do cruzamento IAS-63/ALDAN "S"//GLEN/3/IAC-24, de porte baixo, mostrou resistência ao acamamento e ao agente causal da ferrugem-da-folha e tolerância à toxicidade de alumínio, destacando-se, ainda, quanto à produção de grãos. A linhagem 6 identificou-se como fonte genética de maior número de grãos por espigueta, porte baixo, resistência ao acamamento e à ferrugem-da-folha, e a linhagem 8 apresentou espigas mais compridas e maior número de espiguetas por espiga. Todos os genótipos avaliados, com exceção do cultivar IAC-287 (controle sensível) exibiram elevada tolerância à toxicidade de alumínio.

The Anchorage Mechanics of Maize,Zea mays

The anchorage system of mature maize Zea mays was investigated by combining morphological and anatomical study of the root system with mechanical tests on roots and with studies in which plants were pulled over. The root system is dominated by 20–30 adventitious roots which emerge in rings from the stem base pointing radially downwards and outwards, approximately 30° from the vertical. Roots are strengthened near their base by a heavily lignified exodermis which makes them rigid in bending; distally, strength and rigidity both decrease because roots become thinner and less lignified. When plants were pulled over, a maximum anchorage moment of 5–20 Nm was mobilized at angles of 8–10°, larger plants having stronger anchorage. Movement was initially centred on the leeward side of the stem, anchorage being due to the resistance of both windward and leeward roots to axial motion through the soil and to bending. At displacements over 10°, however, leeward roots buckled under combined bending and compression and the centre of rotation shifted to the windward perimeter of the root system; subsequent movement of the cone of roots and soil was resisted only by the bearing strength of the soil beneath it. The differences between anchorage failure in balsam and sunflowers and that in maize probably results from the lower angular spread and the weakness in compression of the maize roots which prevents the leeward side of the root system from bearing large downward loads. The system behaves more like that of wheat; these results suggest that the lodging resistance of both plants may be improved by increasing the bending strength and angle of spread of the adventitious roots.

Reciprocal recurrent selection for multitrait indices in maize

Reciprocal recurrent selection was carried out with two populations of maize (Zea mays L.) having good combining ability. We selected for higher grain yield, early maturity, shorter plant height and lodging resistance. Two cycles were completed in two years (four seasons), by resorting to late planting of S1 lines for recombination in the main season in which top-cross families were assessed. Top-crosses and selfings were made in the off-season. The original and improved versions of the populations and their crosses were evaluated in multilocation trials. The superiority of the population hybrid was 10.3% for grain yield, 5.5% for plant height and 1.8 days to silk. The improved hybrid had delayed leaf senescence and better resistance to lodging and post-flowering stalk rots. Among the yield components, only ear girth showed improvement. Syn 2 of the improved population cross showed a yield reduction of 6.2% in comparison to Syn 1. Intrapopulation gains were not significant except for lodging resistance in one population.

Studies on breeding for germinability at low temperature of rice varieties adapted to direct sowing cultivation in flooded paddy field in cool region. : VI. Effectiveness of individual selection for germinability at low temperature on some agro-nomic characters in early segregating generations

The present study was carried out in order to clariLy the influence of selection for germinability at low temperature on some agronomic characters in early segregating generations. The local or old variety with higher germinability at low temperature were crossed with a new improved variety with lower germinability and the selection for seed germinability was carried out in the F3 generation to an extent of 20% in both positive and negative directions. F4 Strains were grown from the F3 individuals and divided into two groups based on the presence or absence of selection for grain quality. Yield ability, lodging resistance, plant type and cold resistance were investigated in each strain. First, previous results regarding the genetic mechanisms for seed germinability by the authors were reconfirmed from the continuous variation in the F3 distributions in which few effective Lactors were analysed by statistical methods. It was also indicated that the selection towards high germinability in F3 individuals was effective to some extent in the production of strains of high germinability in later generations. Next, the secondary effects for the agronomic characters by selection were investigated in the F3 and F4 generations. In F3 populations, a significant difference was recognized in the rate of white beliverering rices and the awn length between the selected and nonselected groups for quality. There was a tendency in the variance of the character decrease by the selection with the exception of the awn length, although a significant difference was not recognized. In F4 strains, consistent results were not obtained among characters such as plant type, lodging resistance, grain quality, yield ability and cold resistance. It was shown that the germinability at low temperature was not affected by selection for grain quality. From the results mentioned above, it was demonstrated that the breeding of the promising varieties with the desirable agronomic characters which were characterized by high seed germinability and rapid initial seedling growth under low temperature is possible in direct sowing cultivation in flooded paddy fields in cool temperature regions such as Hokkaido, the northernmost island of Japan.

Analysis of Yield-Determining Process and Its Application to Yield-Prediction and Culture Improvement of Lowland Rice : XCVII. Effect of the nitrogen depletion at different growth stages of the plant type and the lodging resistance of rice plants after heading

Growing rice plants in solution culture under community conditions and stopping nitrogen supply for 21 days at intervals of l0 days at successive growth stages, the authors studied the effects of nitrogen deficiency at different growth stages on the growth, grain yield, plant type and lodging resistance. The results obtained can be summarized as follows: 1. A maximum grain yield (6.84 tons per ha.) was obtained in treatment No.3 which was subjected to nitrogen deficiency for 21 days from 72 to 87 in the leaf-number index (50∼29 days before heading), and the yield was characterized by the highest percentage of ripened grains among the treatments. 2. As the treatment time delayed, the number of panicles per unit area increased, while the number of spikelets per panicle decreased in treatments after the stage of neck-node differentiation. The number of spikelets per unit area ran parallel to the number of panicles per unit area in all the treatments. 3. Since the effectiveness of the nitrogen depletion treatment on the plant growth such as the increase in number of tillers and in dry weight decreased progressively with the delay of treatment time, the treatment at relatively early stages was considered desirable for controlling the plant type in case of an enough number of tillers having been obtained. 4. The most suitable time of nitlogen depletion treatment for improving the plant type as well as increasing the percentage of ripened grains appeared to be the time of Treatment No.3 (72∼87 in the leaf-number index) and No.4 (77∼89 in the leaf-number index) from the viewpoint of the shortening in the length of upper 3 leaves and the controlling of the leaf-area in plants, while it was considered to be the time of Treatment No.2 (61∼78 in the leaf-number index) and No.3 from the view-point of the lodging resistance (which is closely related with the height of plant, the length of lower internodes and the number of culms with 6-th elongated internodes). 5. The high resistance for lodging in Treatment No.2 and No.3 could be characterized by the strong breaking strength at the base part (15 cm from below) of culms in the period of 20-30 days after heading and also by the big bending stress of culms at maturity. 6. On the basis of the facts above mentioned the most reasonable time for improving the plant type and increasing lodging resistance and consequently increasing the percentage of ripened grains as well as yield by means of nitrogen depletion for 21 days was considered to be the period centering around the time of Treatment No.3 (72∼87 in the leaf-number index).

FODDER PRODUCTIVITY OF OATS VARIETIES AND LINES IN COMPETITIVE VARIETY TRIAL IN THE FAR EAST AGRO-CLIMATIC CONDITIONS

A study of the fodder productivity of varieties and selection lines of spring oats was carried out. Field experiments were laid in a competitive study nursery in the fields of a selection crop rotation of the Far East Agricultural Research Institute in 2016-2020. As a result of studying the fodder productivity of oats, varieties and breeding lines were identified: Marshal, Cardinal, Peredovik, Far Eastern fodder, Far Eastern gold 437-05, 392-15, 474-14, combining high grain productivity (from 8.0 t/ha to 8.9 t/ha), green mass (from 79.8 t/ha to 90.3 t/ha) and dry matter (from 11.1 t/ha to 12.8 t/ha). It was found that the duration of the sprouting-sweeping phase depended on the average daily air temperature (r = -0.697) and the amount of precipitation (r = 0.847). Leafiness of plants (r = 0.521), due to the size of leaves (r = 0.643), made a significant contribution to the formation of the yield of green mass in our studies. A positive relationship has been established between productive tillering and grain yield (r = 0.532), green mass yield (r = 0.548), and dry matter collection (r = 0.511). An indirect role in the formation of the yield of green mass of oats is played by plant height (r = 0.451) and lodging resistance (r = 0.421). The yield of green mass of oats in the soil and climatic conditions of the Far East region depends to a greater extent on the leaf area (r = 0.621) than on the plant height (r = 0.451).