Shorter Plant Height Research Articles

Mesotrione 함유 제초제에 대한 벼 생태형간 약해반응 차이

최근에 등록된 mesotrione+pretilachlor(MP) 및 bensulfuron-methyl+mesotrione+pretilachlor+pyriftalid (BMPP)에 대한 벼 생태형간 약해 반응을 조사하기 위해 통일형(장립종) 및 일본형(단립종) 각 3 품종을 표준량과 2배량을 처리하여 온실에서 포트시험한 결과는 다음과 같다. 제초제 MP 및 BMPP에 대한 약해 반응은 벼 생태형에 따라 달랐는데 통일형 품종은 모두 감수성을 보였으나 일본형 벼는 약해가 발생하지 않았다. 통일형 벼는 제초제 처리 후 5일부터 백화증상을 보였고 7일에 약해증상이 뚜렷하였으며 처리 후 14일에는 약해증상이 처리 후 7일 보다 약해지는 경향이었다. 약해정도는 처리농도가 증가할 수록 약해 발생이 심하였다. MP 및 BMPP에 대한 통일형 벼 품종의 초장 억제율은 90g a.i. <TEX>$ha^{-1}$</TEX>(표준량)에서 18~43%, 배량에서 30~50% 억제되었고 건물중은 초장보다 억제가 더 커 표준량에서는 46~73%, 배량에서는 65~82%가 억제되었고 억제정도는 농도가 증가할수록 컸다. 하지만 대부분의 일본형 벼는 제초제 2배에서도 약해증상을 보이지 않았으나 초장 및 건물중이 약간 억제 되었다. 벼 생태형별 MP에 대한 50% 생육억제 농도를 조사한 결과, 통일형 벼는 37g a.i. <TEX>$ha^{-1}$</TEX>로 일본형 벼의 476g a.i. <TEX>$ha^{-1}$</TEX>보다 12.9배나 낮았다. 이상의 결과에서 mesotrione을 함유하고 있는 MP 및 BMPP에 대한 벼 생태형간 반응에 차이가 있고, 초다수형 벼 재배시 초기 잡초 발아전 제초제로서 MP 및 BMPP의 사용을 자제하는 것이 바람직하다. Greenhouse experiment was conducted to evaluate tolerance of six rice cultivars, three Indica<TEX>${\times}$</TEX>Japonica rice (long grain, cv. Dasanbyeo, Segejinmi and Hanareumbyeo) and three Japonica rice (short grain, Nampyung, Ilpumbyeo and Junamjosaeng) cultivars, to mesotrione+pretilachlor (MP) and bensulfuron-methyl+mesotrione+pretilachlor+pyriftalid (BMPP) in transplanting rice. Two herbicides were applied at 90 g and 180 g a.i. <TEX>$ha^{-1}$</TEX> to three to four leaf stage rice at 5 and 15 days after transplanting, respectively. Related study was also conducted to compare <TEX>$GR_{50}$</TEX> for Indica<TEX>${\times}$</TEX>Japonica and Japonica rice cultivars at different MP rates. Response to two herbicides varied with respect to rice cultivars and herbicide rates. All Indica<TEX>${\times}$</TEX>Japonica rice cultivars exhibited susceptible to both MP and BMPP as reflected by increased visual injury, shorter plant height and higher plant dry matter reduction when compared with nontreated rice cutlivars. The degree of foliar chlorosis by MP at 90 g a.i. <TEX>$ha^{-1}$</TEX> was 5~6 at 7 days after treatment(DAT) but it was decreased to 3~6 at 14DAT. The degree of leaf chlorosis treated with 180 g a.i. <TEX>$ha^{-1}$</TEX> MP was 6~7 at 7DAT and it was also decreased to 3~8 at 14 DAT. The plant hight of Indica<TEX>${\times}$</TEX>Japonica rices was inhibited by 18~43% at application of 90 g a.i. <TEX>$ha^{-1}$</TEX> MP and 30~50% at 180 g a.i. <TEX>$ha^{-1}$</TEX> MP. The dry matter reduction was greater than that of plant height inhibition, showing 46~73% at 90 g a.i. <TEX>$ha^{-1}$</TEX> MP and 65~82% at 180 g a.i. <TEX>$ha^{-1}$</TEX> MP. Similar leaf chlorosis injury and growth inhibition of rice cultivars was observed in the BMPP treatment. The injury and growth inhibition by MP and BMPP increased with increase in herbicide rate from 90 g a.i. <TEX>$ha^{-1}$</TEX> to 180 g a.i. <TEX>$ha^{-1}$</TEX>. However, most of the Japonica cultivars are tolerant to MP and BMPP at both rates. There was no visible leaf chlorosis but plant height and dry matter production were slightly reduced at 180 g a.i. <TEX>$ha^{-1}$</TEX>. Based on <TEX>$GR_{50}$</TEX> value determined in reduction of shoot dry weight for MP, the Indica<TEX>${\times}$</TEX>Japonica rice showed 12.9 fold lower compared with the Japonica rice. The result indicates that rice cultivars vary in tolerance to herbicides of MP and BMPP and Indica<TEX>${\times}$</TEX>Japonica rices were more susceptible than the Japonica rices to the MP and BMPP.

Identification and gene mapping of a rice dynamic narrow leaf mutant

Leaf shape is an important trait in crops. Understanding the genetic mechanism underlying leaf shape will enable us to improve plant architecture and consequently crop yields. In the present study, we obtained a dynamic narrow leaf rice mutant by γ -ray radiation, temporarily named dnl1 . Morphological analysis indicated that the dnl1 mutant produced shorter and narrower leaves at the seedling stage when compared with those of the wild type; whereas no significant differences were exhibited at maturity. In addition, the dnl1 mutant also showed longer longevity, shorter plant height, lower seed set and decreased grain number. Genetic analysis showed that the dynamic narrow leaf character was controlled by a recessive gene, located in the region between the STS markers d15 and d20 on the long arm of chromosome 1, with a genetic distance of 0.9 cM and 2.2 cM, respectively. Additional SSR and STS markers were employed for the fine-mapping of Dnl1 . The results indicated that Dnl1 was assigned to the region between M1-Z47 and M1-Z42, cosegregating with d17, M1-Z41, M1-Z43 and M1-Z49; the physical distance of the region was 172 kb long. The findings provide a solid foundation for the cloning of Dnl1 .

DTH8 Suppresses Flowering in Rice, Influencing Plant Height and Yield Potential Simultaneously

The three most important agronomic traits of rice (Oryza sativa), yield, plant height, and flowering time, are controlled by many quantitative trait loci (QTLs). In this study, a newly identified QTL, DTH8 (QTL for days to heading on chromosome 8), was found to regulate these three traits in rice. Map-based cloning reveals that DTH8 encodes a putative HAP3 subunit of the CCAAT-box-binding transcription factor and the complementary experiment increased significantly days to heading, plant height, and number of grains per panicle in CSSL61 (a chromosome segment substitution line that carries the nonfunctional DTH8 allele) with the Asominori functional DTH8 allele under long-day conditions. DTH8 is expressed in most tissues and its protein is localized to the nucleus exclusively. The quantitative real-time PCR assay revealed that DTH8 could down-regulate the transcriptions of Ehd1 (for Early heading date1) and Hd3a (for Heading date3a; a rice ortholog of FLOWERING LOCUS T) under long-day conditions. Ehd1 and Hd3a can also be down-regulated by the photoperiodic flowering genes Ghd7 and Hd1 (a rice ortholog of CONSTANS). Meanwhile, the transcription of DTH8 has been proved to be independent of Ghd7 and Hd1, and the natural mutation of this gene caused weak photoperiod sensitivity and shorter plant height. Taken together, these data indicate that DTH8 probably plays an important role in the signal network of photoperiodic flowering as a novel suppressor as well as in the regulation of plant height and yield potential.

Functional response traits in relation to land use change in the Montado

The socio-economic changes of the last decades have resulted in changes in traditional land uses with consequent abandonment of large farmland areas in the Mediterranean region. We assessed the response of species richness and composition, and species functional traits to decreasing land use intensity in a Montado system, an agro-pastoral system characteristic of the Alentejo, Southern Portugal. Additionally, we investigated whether plant functional types can be established based on the response to decreasing land use intensity in these systems. Consistent with previous studies, species richness decreased sharply after land abandonment, and this was associated with a strong turnover in species composition from grazed to abandoned sites as the vegetation changed from herbaceous to shrub dominated communities. Pronounced differences in functional traits were found for different successional stages. Therophyte life form, short plant height, high specific leaf area (SLA), low leaf dry matter content (LDMC) and small seeds with dispersal structures were dominant in grazed plots. Within abandoned plots, chamaephytes dominated in plots abandoned for 10–15 years and decreased in favour of nanophanerophytes in plots abandoned for 20–30 years. Plant height, LDMC and seed mass increased with abandonment time while SLA decreased. Functional response groups sufficient to describe vegetation change were identified combining life form and SLA. Therophytes with medium SLA were the dominant functional group in grazed areas, while nanophanerophytes with medium or low SLA were associated with later phases of abandonment. At intermediate stages of succession the dominant group was chamaephytes with medium SLA but functional diversity was highest as all the groups, except hemicryptophytes with medium SLA, were represented. These changes in functional composition can be translated into effects on key ecosystem properties. The increase in LDMC indicates an increase in flammability while trends in both LDMC and SLA suggest decreased decomposition, and thereby carbon and nutrient cycling. These will need to be considered in combination with consequences for other ecosystem properties for future management.

Güneydoğu Anadolu ekolojik koşullarında bazı arpa (Hordeum vulgare L.) çeşitlerinin verim ve verim öğelerinin belirlenmesi

In this study; yield, yield components and some quality parameters of nine summer and alternate barley varieties (Akhisar-98, Bilgi-91, Bornova-92, Kaya, Sur-93, Suleymanbey-98, Sahin-91, Serifehanim-98 ve Vamikhoca-98) being suitable for South East Anatolia Region and registered by different Agricultural Research Institutes were determined in 2003-2004 growing season. According to the results, varieties in Ceylanpinar were ten days earlier and had shorter plant height, higher hectoliter weight and protein content than those in Diyarbakir. The varieties had high performance for the other characters studied in Diyarbakir conditions. Seed yield of varieties were ranged 388-487 kg da-1. While the highest mean seed yield was 487 kg da-1 for Vamikhoca-98, the least mean seed yield was 388 kg da-1 for Bornova-92. It was found a tendency of increase in Ceylanpinar conditions with 40 % decrease in seed yield. Vamikhoca-98, Suleymanbey-98 and Akhisar-98 were advised for Diyarbakir condition; Akhisar-98, Sahin-91 and Vamikhoca-98 were found to be suitable for Ceylanpinar.

Variation for qualitative and quantitative traits and identification of trait-specific sources in new sorghum germplasm

Assembling, collecting and characterising the unique germplasm accessions for morphological and agronomic characteristics are essential activities of a dynamic genebank. The phenotypic diversity and agronomic performance of 667 newly acquired sorghum germplasm accessions, representing five basic races, eight intermediate races and two wild species, originating from 34 countries were assessed for seven qualitative and eight quantitative traits. Large variability was observed among these accessions for various qualitative and quantitative traits. Trait-specific accessions for early flowering (108), short plant height (8), medium panicle exsertion (34), and medium-sized seeds (78) have been identified. The diverse trait-specific promising accessions have the potential for their utilisation in future breeding programs for developing improved sorghum cultivars with a broad genetic base. The hierarchical cluster analysis grouped five races, six intermediate races, and two wild species into three clusters. The present study has played a significant role in filling up the gaps and has also identified region(s) to carry out future explorations, and in providing the trait-specific germplasm for use by the breeders.

Heterosis, Combining Ability and Components of Genetic Variance in Faba Bean (Vicia faba L.)

The present investigation was carried out at the Agricultural Research Station, Faculty of Agriculture, Alexandria University to evaluate seven faba bean varieties (four local and three introduced) in the diallele cross set. Twenty one crosses were constituted in the winter season of 2006/2007, whereas parents and crosses were evaluated in a yield trial, in winter season of 2007/2008, in a randomized complete block design of three replications. Results revealed highly significant variations within parents and F1 genotypes indicating a wide genetic variability for the studied characters and the possibility of genetic improvement using such genetic pools of faba bean. Several crosses recorded significant positive heterosis percentages relative to mid parent and better parent for seed yield per plant and 100-seed weight ranging from 17.46-84.95%, 22.47- 68.49%, 8.53-23.26% and 10.43-18.64% relative to MP and BP for each character, respectively. Both general (GCA) and specific (SCA) combining abilities were significant for all studied characters revealing the important role of both additive and dominant components in the inheritance of the studied characters. Giza Blanca proved to be a good combiner for all studied characters except number of pods per plant and maturity time. Several crosses exhibited significantly positive SCA effects for studied characters especially Giza 716 × ILB 450 and ILB 450 × Giza Blanca which exhibited highly significant and positive SCA effects for seed yield per plant and 100-seed weight. Heritability in narrow sense was high for 100- seed weight (0.54) and short plant height (-0.51) while it was low for seed yield per plant.

Morphological distinctiveness and metroglyph analysis of fifty accessions of West African okra (Abelmoschus caillei) (A. Chev.) Stevels

The Morphological uniqueness and metroglyph analysis of 50 accessions of West African okra (Abelmoschus caillei (A Chev.) Stevels) were assessed under three agro-ecological environments at Abeokuta, Ibadan and Mokwa in Nigeria. They were grown in a Randomized Complete Block Design with three replications; data were collected on 5 randomly selected plants from each plot. Data on twenty-one agronomic characters were collected; eleven traits were subjected to metroglyph analysis to investigate the extent of distinctiveness among the 50 accessions. The eleven agronomic characters representing the most commonly used in distinguishing between okra genotypes were used to construct a metroglyph chart. All accessions were grouped into seven distinct groups. The index scores ranged from 19.0 to 42.3 with groups I and VII showing the two extremes among the 50 accessions evaluated. The fruit surface of Akure-2-2 and Akure-1-1 were smooth while Akure-2-9 and Akure-2-4 showed slightly prickly fruits. This suggests that accessions from Akure town in Ondo state of Nigeria were domesticated to large extent and possibly are more related. The metroglyph showed that accessions with very poor yield had short plant height, an indication that for West African genotype okra to produce substantial yield, it must possess a strong stem, hence early planting is encouraged. Key words: Abelmoschus caillei, accessions, genotype, index score, metroglyph.

Comparison of Yield, its Components, and Other Agronomic Traits Of Different Exotic Whert Cultvars

Aiming to evaluate the CIMMYT durum wheat (Triticum turgidum var. durum) cultivars, yield trials for 49 entries (International nursery 29IDYT) IN comparison with the local Gerardo cultivar were conducted at al-Latifyia Experimental Station during 1997/1998-1999/ 2000. Alpha lattice design with tow replictions for the 1st season and a randomized complete block design with three replications for the 2nd and 3rd seasons were used. Pooled analysis for the three seasons was practiced. Results revealed that days to heading, plant height, weight of 1000 kernel, and grain yield were affected significantly by the different cultivars under investigtion. No significant effect for the different sowing seasons yield only, whereas, the cultivars x sowing seasons interactions showed significant effects for almost all traits under investigation. In general, days to heading, plant height, and weight of 1000 kernel were ranged between 105-113.7 days, 84.4-101.0 cm., and 37.6-48.1 g, respectively. These results reflect the expanded variation in grain yield among cultivars. All entries out yielded 3446 to 5067 kg/ha. Twenty-one. 12, and 18 CIMMYT introduved durum wheat cultivars were exceeded in early heading, short plant height, and high grain weight over the local cultivar, respetively. The CIMMYT entries 2 and 28 (Yavaros 79 CM9799-126M-1M-5Y-0M and MINIMUS/COMB DUCK 2//CHAM 3 D98225-A-3Y-04M=040YRC-6M-0Y), respectively of the mentioned nursery gave the highest grain yield. Which was over than 5 t/ha with an increase of 25% over the local cultivar.

Gene mapping of brachytic stem and its effects on yield-related traits in soybean

Plant height, determinate growth habit, and brachytic stem are 3 major plant-type traits of soybean. In this report, a population of 151 recombinant inbred lines (RILs) derived from the cross of Bogao (high stature, indeterminate growth habit, and normal stem) and Nannong 94-156 (short stature, determinate growth habit, and brachytic stem) was used to map genes and quantitative trait loci (QTLs) for 3 plant-type traits and to reveal the effects of brachytic stem on yield-related traits including seed yield, apparent biological yield, apparent harvest index, plant height, and days to maturity. The results indicated that brachytic stem (sb) and determinate growth habit (dt1) were mapped on linkage groups B2 and L, respectively. Two major QTLs related to plant height were detected and mapped on linkage group L near dt1, and 0.6 cM above the Sb locus on linkage group B2 across 2 years. These 2 QTLs explained 15.1% and 52.7% of the phenotypic variation, and decreased plant height by 9.2 and 17.6 cm, respectively. It was found that only one QTL was detected and mapped on linkage group L near dt1 across 2 years. Lines with brachytic stem had shorter plant height, lower biomass, yield, and harvest index, and essentially no differences in days to maturity when compared with normal stem lines.

Allelopathic potential of K21, selected as a promising allelopathic rice

The agronomic characteristics of a newly bred potent allelopathic rice, K21, including morphological appearance, resembled its female parent, Dongjinbyeo, except for 8 days’ earlier heading and 9 cm shorter plant height. The water extract of K21 showed a greater inhibitory effect on the shoot and root growth of barnyardgrass than its female parent, but less than the male parent, Kouketsumochi. At the highest extract concentration of 5.0%, the inhibitory effect of K21 on the shoot growth of barnyardgrass was ≈ 64%, similar to its male parent. The dry weight of the barnyardgrass shoot was reduced by 13.0% when grown with K21 and 30.2% when grown with its male parent. There was no inhibitory effect on the shoot dry weight of barnyardgrass when grown with the female parent. The activity of cinnamic acid 4‐hydroxylase in K21 was ≈ 1.8‐fold higher than that of the female parent, but significantly lower than that of the male parent. The ρ‐coumaric acid content in K21 was ≈ 60% higher than that of the female parent, but it was about half of the male parent. The total amount of phenolic compounds in K21 was ≈ 11.5% higher than in the female parent, but about half of the male parent. The results obtained suggest that the newly bred K21 contains desirable allelopathic traits derived from the male parent, Kouketsumochi, and acceptable agronomic traits from its female parent, Dongjinbyeo.

Irrigated Corn and Soybean Response to Nitrogen under No‐Till in Northern Colorado

Irrigated, no‐till (NT) production systems can potentially reduce soil erosion, fossil fuel consumption, and greenhouse gas emissions compared with conventional till (CT) systems. Including a legume in the rotation may also reduce N fertilizer requirements. Nitrogen fertilization (6 N rates) effects on irrigated, corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] yields in a corn–soybean rotation were evaluated for 5 yr on a clay loam soil to determine the viability of an irrigated NT system and N needs for optimum crop yield. Corn grain yields were significantly increased by N fertilization each of 3 yr in the rotation, but soybean grain yields (2 yr) did not respond to N fertilization, averaging 2.79 Mg ha−1. Three year average corn grain yields were near maximum with an available N (AN) (soil + fertilizer + irrigation water N) level of 257 kg N ha−1. Nitrogen use efficiency (NUE) by corn and soybean, based on grain N removal, decreased with increasing AN level and ranged from 155 to 46 and 88 to 18 kg grain kg−1. AN for the low and high N treatments for corn and soybean, respectively. Estimated total N required to produce one Mg grain at maximum yield averaged 20 kg N for corn and 54 kg N for soybean. Corn residue increased with increasing N rate, but soybean residue was constant across N rates. Excellent irrigated, NT corn yields were obtained in this corn–soybean rotation for northern Colorado, but soybean yields were only marginally acceptable. Short soybean plant height (30–40 cm) and shattering made combine harvest difficult resulting in significant grain loss. Improved soybean cultivars are needed for this area to make a corn–soybean rotation a viable production system.

Unrecorded naturalized species: Papaver setigerum DC. (Papaveraceae) and Veronica serpyllifolia L. (Scrophulariaceae)

Two naturalized allien species are reported from Jeju Island: Papaver setigerium collected from the ground along the road in lowland Veronica serpyllifolia collected from the roadside and ranches on alt. 400-800 m. P. setigerium is similar to P. somniferum, but different from the latter by plant height of 30-70 cm, shorter discoid stigma than fruit in diameter, somewhat sparsely bristly on stems, leaves and calyxes. V. serpyllifolia is similar to V. tenella in morphology, but different from the latter by short plant height, petiolated leaves on lower stem and serrated leaf margins.

Registration of ‘Hallam’ Wheat

'Hallam', selected from the cross 'Brule'/'Bennett'//'Niobrara', is a hard red winter wheat (Triticum aestivum) cultivar developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS. It was released in 2005 primarily for its superior adaptation to rainfed wheat production systems in eastern Nebraska. The average Nebraska rainfed yield of Hallam of 4110 kg/ha (41 environments from 2002 to 2004) was greater than 'Wahoo' (4030 kg/ga), 'Alliance' (3880 kg/ha) and 'Harry' (4000 kg/ha), but lower than 'Millenium' (4180 kg/ha) and 'Wesley' (4210 kg/ha). Hallam is moderately early in maturity (142 days after 1 January), approximately 2.5 and 1.2 days earlier than Millenium and Wesley, respectively. It is a semidwarf cultivar with a medium short coleoptile (46 mm) and mature plant height (86 cm) that is 3 cm shorter than Millenium and 6 cm taller than Wesley. Hallam is moderately resistant to stem rust (Puccinia graminis f.sp. tritici), stripe rust (P. striiformis f.sp. tritici) and Hessian fly (Mayetiola destructor).

High Yielding Performance of Soybean in Northern Xinjiang, China

The experimental site (Shihezi, Xinjiang, China) is located in an arid area of central Asia with abundant solar radiation of almost 10 daily sunshine hours from April to September. The yield potential in this area appears to be high if sufficient water is supplied. The yields of five soybean (Glycine max (L.) Merr.) cultivars including three semi-indeterminate Chinese cultivars (Shidadou 1, Xindadou 1 and Suinong 11) and two determinate Japanese cultivars (Toyomusume and Toyokomachi) were evaluated over three years. These cultivars were grown under drip irrigation, a high planting density (22.2 plants m-2) and heavy applications of farmyard manure (15 t ha-1). Each cultivar showed a high leaf area index (LAI). In particular, the maximum LAI was greater than 7 over the three years in Shidadou 1 and Toyokomachi. The three Chinese cultivars with a high plant height had a low LAI in the upper layers of the canopy, but the two Japanese cultivars with a short plant height had a higher LAI in the middle or upper layers. Toyokomachi and Shidadou 1 had the highest seed yield, followed by Toyomusume. In particular, the seed yield of Toyokomachi was as high as 8.67 t ha-1 on the average of the three years. These high-yielding cultivars had more than 60 pods per plant (1350 m-2). The high yields in this experiment could be due to the large amount of intercepted radiation owing to the high LAI and abundant solar radiation, frequent and sufficient irrigation by the drip irrigation, and large number of pods as a sink.

Spring Growth and Use of Cool-Season Graminoids in the Nebraska Sandhills

Upland sites in the Nebraska Sandhills are dominated by warm-season grasses, although cool-season graminoids often produce from 10% to 40% of the herbage. The grazing season on uplands traditionally begins when warm-season grasses have initiated rapid growth, which coincides with declining nutrient density of cool-season plants. Earlier initiation of grazing would improve the efficiency of use of cool-season plants. A study was conducted in 2001 and 2002 to characterize the growth of cool-season species on upland range and to determine the use and herbage production in response to spring grazing date and stocking rate. Grazing dates were 10 April, 1 May, and 22 May, combined with stocking rates of 3, 6, and 9 AUD (animal unit days)·ha−1. Needleandthread (Stipa comata Trin. & Rupr.) and sedges (Carex spp.) accounted for an average of 48% of the spring herbage yield. Amount of total current-year herbage ranged from 114 to 472 kg·ha−1 over the grazing dates. Overall, paddock use of needleandthread and sedges averaged 11% and 4%, respectively. Use on 10 April averaged 61% of that observed on 1 and 22 May, likely because of short plant height (5 cm). Residual (prior-year) herbage probably was a substantial component of animal diets on 10 April. Increasing stocking rate resulted in greater herbage use (% weight removed) and percentage of plants grazed (P < 0.1). Total herbage yield in mid-June (1 130 kg·ha−1) and mid-August (1 350 kg·ha−1) was greatest when paddocks were grazed in April, and it declined by approximately 20% when grazed in May (P < 0.1). Overall, upland grazing strategies that include a grazing period in early May will result in greater utilization of cool-season species, but summer yield will be reduced. However, utilization of cool-season species in the spring would be advantageous, because they are being consumed at a time when their nutritive value and palatability are greater.

Spring Growth and Use of Cool-Season Graminoids in the Nebraska Sandhills

Upland sites in the Nebraska Sandhills are dominated by warm-season grasses, although cool-season graminoids often produce from 10% to 40% of the herbage. The grazing season on uplands traditionally begins when warm-season grasses have initiated rapid growth, which coincides with declining nutrient density of cool-season plants. Earlier initiation of grazing would improve the efficiency of use of cool-season plants. A study was conducted in 2001 and 2002 to characterize the growth of cool-season species on upland range and to determine the use and herbage production in response to spring grazing date and stocking rate. Grazing dates were 10 April, 1 May, and 22 May, combined with stocking rates of 3, 6, and 9 AUD (animal unit days) ha-1. Needleandthread (Stipa comata Trin. Rupr.) and sedges (Carex spp.) accounted for an average of 48% of the spring herbage yield. Amount of total current-year herbage ranged from 114 to 472 kg ha-1 over the grazing dates. Overall, paddock use of needleandthread and sedges averaged 11% and 4%, respectively. Use on 10 April averaged 61% of that observed on 1 and 22 May, likely because of short plant height (5 cm). Residual (prior-year) herbage probably was a substantial component of animal diets on 10 April. Increasing stocking rate resulted in greater herbage use (% weight removed) and percentage of plants grazed (P &lt; 0.1). Total herbage yield in mid-June (1 130 kg ha-1) and mid-August (1 350 kg ha-1) was greatest when paddocks were grazed in April, and it declined by approximately 20% when grazed in May (P &lt; 0.1). Overall, upland grazing strategies that include a grazing period in early May will result in greater utilization of cool-season species, but summer yield will be reduced. However, utilization of cool-season species in the spring would be advantageous, because they are being consumed at a time when their nutritive value and palatability are greater.

Ethylene insensitive and post-harvest yellowing retardation in mutant ethylene response sensor (boers) gene transformed broccoli (Brassica olercea var. italica)

A mutant broccoli ers (ethylene-response-sensor, boers) gene was obtained through site directed mutagenesis by replacing the isoleucine with phenylanine at the 62th residue. Two plasmids were constructed with this mutant gene regulated by the CaMV 35S promoter together with the nptII (kanamycin resistance gene) coding sequence and hpt (hygromycin resistance gene), respectively, for the pBI-mERSI62F and pSM1H-mERSI62F plasmids. Genetic transformation of the above two constructs via A. tumefaciens has been conducted to evaluate their effects on floret yellowing of harvested broccoli. Over a hundred transformants have been obtained on the selected cotyledon and hypocotyl explants. PCR and Southern analysis demonstrated integration of the transgenes in the transformants. However, through Southern hybridization, we determined that multi-site integration and DNA rearrangements had occurred in most transformants. Morphological and characteristic alternation such as slower plant growth, shorter plant height, easy branching, late bolting, and relative higher mortality in comparison with other transgenes were noted in some transformants. Transgenic lines showing delayed senescence in leaves and floral heads were obtained. The expression of transgene was confirmed by Northern blot analysis. The transformed progenies also showed ethylene insensitivity in seed germination, detached leaves and harvested florets. Nevertheless, in most lines, the yellowing was only delayed 1–2 days.

Geographical patterns of diversity in pearl millet germplasm from Yemen

Yemen differs considerably from many other countries in its extreme variation in elevation. A set of 229 pearl millet germplasm accessions collected from diverse elevations of Yemen was characterized for 12 morpho-agronomic characteristics at ICRISAT, Patancheru, India. Analysis of variance revealed highly significant differences (P < 0.001) among elevational zones for flowering, plant height and seed weight when evaluated in the post-rainy season and for panicle length and thickness when evaluated in the rainy season. The differential performance of accessions for flowering and plant height during the rainy and post-rainy seasons at ICRISAT, Patancheru reflected the photoperiod and temperature sensitivity of the accessions. Shannon-Weaver diversity indices indicated high diversity from low elevations for flowering and plant height. The results of the present study imply that environmental factors such as elevation, temperature and rainfall are the important determinants of variation patterns of pearl millet in Yemen and pearl millet germplasm from high elevations of Yemen is a good source for early maturity, cold tolerance, short plant height and large seeds.

Antisense gibberellin 3β-hydroxylase발현 형질전환벼

GA 생합성에 결정적 역할을 하는 GA 3<TEX>$\beta$</TEX>-hydroxylase를 pIG121-Hm 벡터에 GUS유전자를 빼고 antisense로 클로닝하여 이를 동진벼에 도입한 결과 17개체의 절간신장이 억제된 형질전환한 식물체를 얻을 수 있었다. 일반 재배 동진벼를 대조군으로 하여 비교하였을때 antisense GA 3<TEX>$\beta$</TEX>-hydroxylase 유전자가 형질 도입된 식물체의 획득형질은 평균적으로 대조군에 비해 절간 신장의 억제가 확인되었다. 절간신장의 억제가 보인 개체의 엽육조직을 co취하여 Southen blot hybridization분석 결과 3개의 line에서 모두 single copy로 도입된 것으로 나타났다. 이로써<TEX>$T_o$</TEX> 식물체 내에 antisense GA 3<TEX>$\beta$</TEX>-hydroxylase 유전자를 내포하고 있는 것으로 확인되었다. 이것은 antisense GA 3<TEX>$\beta$</TEX>-hydroxylase 유전자가 생체내에서 직접 또는 간접적으로 GA 3<TEX>$\beta$</TEX>-hydroxylase유전자의 발현에 관여한 것이라 사료되어진다. During plant development, active gibberellins (GAs) control many aspects of plant growth and development including seed germination, stem elongation, flower induction, anther development and seed growth. To understand the biosynthesis and functional role of active GAs in high plants, this study investigated GA 3<TEX>$\beta$</TEX>-hydroxylase gene en-coding <TEX>$GA_1$</TEX> and<TEX>$GA_4$</TEX> catalizing last step in GA biosynthetic pathway. The antisense GA 3<TEX>$\beta$</TEX>-hydroxylase gene was inserted into expression vector, pIG121-Hm. Calli derived from mature seeds of rice (Oryza satiiva L. cv. Donjinbyeo) were co-cultivated with Agrohacterium tumefaciens EHA101 earring a pIG121-Hm containing hygromycin resistance (<TEX>$Hyg^r$</TEX>) and antisense GA 3<TEX>$\beta$</TEX>-hydroxylase gene. Seventeen transgenic plants obtained inhibiting GA 3<TEX>$\beta$</TEX>-hydroxylase. Transgenic plants had shorter plant height more than that of the Dongjinbyeo. Stable integration of antisense GA 3<TEX>$\beta$</TEX>-hydroxylase gene was confirmed by polymerase chain reaction of genomic DNA isolated from the leaf organs of the <TEX>$T_o$</TEX> generation.