A biologically-consistent stand growth model for loblolly pine in the Piedmont physiographic region, USA

A theory-influenced dynamical stand growth model formulation described well the behavior of thinned and unthinned loblolly pine plantations. A simplification containing few free parameters performed as well as a fully parametrized version. It seems particularly well suited to situations where available data is scarce. The stand model can be interfaced to additional climate, nutrition and carbon cycling modules for studying the effects of a changing environment.     

苦瓜杂交制种技术研究

苦瓜杂交制种父母本在上午7～9时,且每朵雄花授2～4朵雌花,授粉后30天左右采收,种子各项生理指标均达到较理想的水平,可显著提高杂交种子的产量和质量.     

施钾条件下杂交水稻氮磷养分吸收利用特点

对浙江省金华市郊区石门农场灌溉稻区进行连续4年定位钾肥试验,结果表明,钾素促进氮磷养分向水稻穗部的输入,故在增产的基础上,同不施钾处理比较,施钾后杂交稻氮的总吸收量增加7.1～9.3kg/hm2,利用效率提高3.7～7.1%;磷的总吸收量增加1.0～2.0kg/hm2,利用效率提高2.0～7.7%。同常规稻比较,每季杂交稻氮和磷的平均总吸收量分别高出7.6kg/hm2和1.2kg/hm2;氮和磷的利用效率平均高出3.1kg/kg和34.7kg/kg;在养分的吸收、积累以及利用效率方面表现出明显的生理优势[1]。因此,在杂交水稻的生产实践中,应相对增加钾肥的施入量,从而提高氮肥和磷肥的利用效率。     

Morphological quality of sweet corn (Zea mays L.) ears as response to soil moisture tension and phosphate fertilization in Campeche, Mexico

In Mexico, corn production, part of which is sweet corn, is mainly destined for human consumption. In the present work, the morphological quality of sweet corn ears was assessed in response to four levels of soil moisture tension indicating irrigation start (−5, −30, −55, and −80 kPa) and three levels of phosphate fertilization (60, 80 and 100 kg ha⁻¹) in carstic soils in the south-east of Mexico. A factorial experimental design with three replicates was used. The following variables were determined: fresh weight (SCFWh), dry weight (SCDWh), diameter (SCDh), and length (SCLh) of sweet corn ears, all without husk, as well as number of kernels (NKxE), number of unfilled kernels (NUK), number of rows (NRxE), and dry kernel weight per ear (DKW). Yield of fresh (YFSCh) and dry (YDSCh) sweet corn ears, both without husk, and the harvest index (HI) were also determined. HI did not show significant statistical differences among irrigation or fertilization treatments. Regarding the other variables, the effect of the more humid treatments (−5 and −30 kPa) and the effect of the higher phosphorus doses (80 and 100 kg ha⁻¹) were statistically equal (P ≤ 0.01) with the lowest NUK and the highest values of all other variables; therefore, irrigation start at soil moisture tension of −30 kPa and phosphate fertilization application of 80 kg ha⁻¹ are recommended. At this level of soil moisture, the mean values over the three fertilization levels and all the replicates, obtained for SCFWh, SCDh, SCLh and NKxE were 198.5 g, 4.39 cm, 26.72 cm and 467 grains, respectively. According to the regression models, moisture tensions from −11.8 to −24.0 kPa, and phosphate fertilization doses from 87.7 to 102.2 kg ha⁻¹ minimize NUK and maximize the values of the rest of the variables. The highest irrigation water use efficiency was found in the moisture tension treatment of −30 kPa with an increase of 27 kg ha⁻¹ ears for each millimeter of applied irrigation water.     

冀番135应用优势及日光温室栽培技术研究

在专项试验与综合配套栽培技术研究及生产试验示范的基础上,系统分析了日光温室番茄新品种冀番135的生育特性、生产适应性、产量及抗性优势,介绍了冀番135番茄日光温室配套栽培技术。     

Effect of levels and sources of nitrogen on concentration and uptake of nitrogen by a high yielding variety and a hybrid of rice

Field experiments were made on a sandy clay loam soil at the Indian Agricultural Research Institute, New Delhi to study the effect of levels and sources of nitrogen on concentration and uptake of nitrogen by a high yielding variety Pusa 834 and a hybrid PRH3 of rice. Nitrogen concentration in hybrid PRH 3 remained lower than in Pusa 834, but N uptake was significantly more in the hybrid PRH 3. Nitrogen fertilization increased N concentration as well as N uptake by rice. At 30 days after transplanting (DAT) N uptake was more in Pusa 834, but at 60 DAT and at harvest hybrid PRH 3 recorded significantly more N uptake than Pusa 834. Use of neem oil blended urea (PNGU) and neem coated urea (NCU) increased N concentration and uptake by rice in both Pusa 834 and hybrid PRH 3. Use of neem coated/blended urea is recommended for rice.     

甬优9号在三明市的种植表现及关键栽培技术

甬优9号在三明市试种表现高产稳产、产量潜力大。该文总结了甬优9号在三明市的种植表现,并提出高优关键栽培技术。     

西葫芦新品种晋西葫芦4号的选育

西葫芦新品种晋西葫芦4号是以国外西葫芦品种的分离后代经多代自交选育而成的纯合自交系D-95-2为母本,以从我国地方品种白皮西葫芦中选育的稳定自交系E-96-8为父本杂交育成的早熟一代杂交种。该品种属短蔓密植类型,极早熟;嫩瓜皮色为鲜嫩的浅绿色,带细网纹,长筒形,光泽度好;植株生长势强,雌花多,瓜码密,耐低温、弱光,丰产,抗病,667m2产量5000kg左右。适合我国北方大部分地区早春各种保护地及露地栽培。     

香菇双单杂交育种初步研究

选用香菇的一个野生株（Ｑ）与一个栽培株苏香（Ｓ）的４种孢子单核体进行双单杂交，获得四个杂交后代。栽培结果表明：１，２，４号菌株产量明显高于双亲产量，其中以２号菌株产量最高，其生物转化率为８６９１％，产量优势为２１２９％，３号菌株产量高于双核体亲本Ｑ，其杂种优势显著。     

早熟茄子新品种蓉杂茄1号的选育

蓉 杂茄１ 号是 用地方品 种单株系 选的优 良自交系８５０１ 作 母本，８６０３ 作 父本配制 的早熟茄 子 一 代 杂 种 ， 果 实 长 棒 形 、深 紫 色、光 泽 度 好。 单 果 质 量 约 ２６５ ｇ ， 平 均 产 量 ３ ５００ ｋｇ ·（６６７ ｍ ２） － １ ，较 抗病，适 合于长江 流域栽培 。