[Objective] The study aimed at investigating the effects of different geographic sites, soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice. [Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials, field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009. A total of four nitrogen application levels were set as follows: by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer, extra 0, 90, 150 and 210 kg/hm2 of nitrogen fertilizer (in which, base fertilizer, base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%, 20% and 20%.) was applied, respectively. In the split-plot design, fertilizer was considered as the main factor while rice variety was taken as the secondary factor. A total of eight treatments were set with three replications. [Result] Highly significant differences of grain yield were found among seven locations, two varieties, four nitrogen application levels, interactions of site variety and site nitrogen application level, but the interaction of variety nitrogen application level had no significant influence on rice yield. There were highly significant effects of site, varieties and nitrogen application level on dry matter production, nitrogen content, nitrogen utilization efficiency. Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found; and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites, chemical quality of soil and the levels of nitrogen application. [Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.

[Objective] The paper was to summarize the research of system of rice intensification (SRI) technology in China. [Method] Through combination screening and factor analysis, the effect of appropriate system of rice intensification technology on yield formation of rice was studied. [Result] The technology had strong adaptability with good effort of yield increase in China, which improved air and light in fields, reduced the incidence of sheath blight, increased photosynthetic capacity of rice plants, increased root activity, enhanced nutrient transportation, increased the rate of paddy milled rice, reduced the chalky grain rate, and simultaneously saved input and labor, increased revenue. [Conclusion] System of rice intensification broke the China's traditional practice of larger planting density, and preliminarily demonstrated a larger yield potential.

Um experimento foi conduzido em câmara de crescimento da Embrapa Milho e Sorgo, MG, visando avaliar características da rizosfera de genótipos de milho contrastantes na eficiência de uso de P, por meio da determinação do comprimento e densidade de pelos radiculares, do pH da rizosfera e da diversidade funcional bacteriana associada à rizosfera. Utilizou-se amostra de um Latossolo Vermelho distrófico, que, após a correção da acidez, recebeu adubação com N, K e micronutrientes. No tratamento correspondente ao nível alto de P, adicionaram-se 174 mg kg-1 de P. Como unidade experimental, utilizou-se rizobox de PVC, que recebeu 2,2 dm-3 de terra. O delineamento experimental foi o inteiramente casualizado, com três repetições, em arranjo fatorial 5 x 2, correspondendo a cinco genótipos (H1, H2 e H3 = híbridos eficientes, H4 e H5 = híbridos ineficientes) e dois níveis de P (baixo = 3 mg dm-3; alto = 29 mg dm-3). Aos 18 dias do transplantio, verificou-se que as raízes nodais dos híbridos H3 e H2 apresentaram maiores comprimentos de pelos radiculares. Em geral, o pH da rizosfera dos diferentes genótipos foi maior do que o pH não rizosférico, independentemente do nível de P. O pH da rizosfera de raízes laterais foi superior ao das nodais. Sob baixo nível de P, os híbridos H2, H5 e H4 mostraram maior variação de pH rizosférico em relação ao não rizosférico. Os híbridos H5 e H3 apresentaram maior atividade funcional microbiana na rizosfera. Sob baixo nível de P no solo, os índices de diversidade funcional microbiana, também, apresentaram maiores valores. A rizosfera dos híbridos H1, H2, H3 e H5 apresentou o mesmo perfil metabólico microbiano quando as plantas foram cultivadas sob baixo nível de P. As variações nas características da rizosfera não permitiram identificar padrões relacionados com a eficiência de uso de P nos materiais genéticos utilizados. | An experiment was conducted in a growth chamber to evaluate characteristics of the rhizosphere of maize genotypes contrasting in P-use efficiency, by determining length and density of root hairs, the rhizosphere pH and the functional diversity of rhizosphere bacteria. A sample of a Red Oxisol was limed and fertilized with N, K and micronutrients. In the treatment with the highest P level, 174 mg kg-1 P was added. Each experimental unit corresponded to a PVC rhizobox filled with 2.2 dm-3 soil. The experiment was completely randomized with three replications in a 5 x 2 factorial design, corresponding to five genotypes (H1, H2 and H3 = P-efficient hybrids, H4 and H5 = P-inefficient hybrids) and two P levels (low = 3 mg dm-3, high = 29 mg dm-3). It was found that 18 days after transplanting, the nodal roots of the hybrids H3 and H2 had the longest root hairs. In general, the pH in the rhizosphere of the different genotypes was higher than in non-rhizosphere soil, irrespective of the P level. The pH was higher in the rhizosphere of lateral than of nodal roots. At low P levels, the pH variation of the hybrids H2, H4 and H5 was greater in rhizospheric than in non-rhizospheric soil. The functional microbial activity in the rhizosphere of the hybrids H3 and H5 was highest. At low soil P levels, the indices of microbial functional diversity were also higher. The microbial metabolic profile in the rhizosphere of hybrids H1, H2, H3, and H5 remained unaltered when the plants were grown at low P. The variations in the rhizosphere properties could not be related to patterns of P-use efficiency in the tested genotypes.

The aim of this paper was to evaluate the effect of two levels of phosphorus in soil (high and low P levels) on dry mass attributes and root characteristics in eight maize lines with different genetic backgrounds and origins. The experimental design was randomized blocks with three replications. The evaluation was performed 21 days after sowing. The WinRhizo program of images analysis was used for the root morphology. There were no differences between the two P levels for the dry mass attributes. However, root morphology of L13.1.2 strain performed the highest surface area and total root length, length of thin and very thin roots in low P concentration. The digital image analyses of root systems allowed efficient discrimination of maize genotypes in environments with low P levels.

Sorghum midge, Stenodiplosis (Contarinia) sorghicola (Coquillett) is an important pest of grain sorghum world-wide. Considerable progress has been made in screening and breeding for resistance to sorghum midge. However, some of the sources of resistance have become susceptible to sorghum midge in Kenya, in eastern Africa. Therefore, the wild relatives of Sorghum bicolor were studied as a possible source of new genes conferring resistance to sorghum midge. Midge females did not lay eggs in the spikelets of Sorghum amplum, Sorghum bulbosum, and Sorghum angustum compared to 30% spikelets with eggs in Sorghum halepense when infested with five midge females per panicle under no-choice conditions. However, one egg was laid in S. amplum when infested with 50 midges per panicle. A larger number of midges were attracted to the odours from the panicles of S. halepense than to the panicles of Sorghum stipoideum, Sorghum brachypodum, S.angustum, Sorghum macrospermum, Sorghum nitidium, Sorghum laxiflorum, and S. amplum in dual-choice olfactometer tests. The differences in midge response to the odours from S. halepense and Sorghum intrans were not significant. Under multi-choice conditions, when the females were also allowed a contact with the host, more sorghum midge females were attracted to the panicles of S. bicolor compared with S. amplum, S. angustum, and S. halepense. In another test, numerically more midges responded to the panicles of IS 10712 compared with S. halepense, whereas the differences in midge response to the panicles of ICSV 197 (S. bicolor) and S. halepense were not apparent, indicating that S. halepense is as attractive to sorghum midge females as S. bicolor. The wild relatives of sorghum (except S. halepense) were not preferred for oviposition, and they were also less attractive to the sorghum midge females. Thus, wild relatives of sorghum can prove to be an alternative source of genes for resistance to sorghum midge | Sharma, Franzmann, 'Host-plant preference and oviposition responses of the sorghum midge, Stenodiplosis sorghicola (Coquillett) (Dipt., Cecidomyiidae) towards wild relatives of sorghum', Journal of Applied Entomology, vol. 125(3), pp.109-114, Wiley, 2011

It is well known that the parasitic weed Striga asiatica (L.) Kuntze can be suppressed by Striga-tolerant sorghum (Sorghum bicolor L. Moench) cultivars, Desmodium intortum (Mill.) Urb. (greanleaf desmodium), and by fertilization with nitrogen. The study objective was the assessment of Striga control provided by integration of Desmodium density, timing of sorghum-Desmodium intercrop establishment, and nitrogen fertilization. Growth responses and yield of three sorghum cultivars were measured in three pot experiments. A soil naturally infested with Striga was used, and that part of the soil which served as uninfested control was chemically sterilised. Striga numbers and growth were affected significantly by sorghum cultivars, sorghum-Desmodium intercrop ratios, timing of the sorghum-Desmodium association, as well as by their interactions. Desmodium caused 100% suppression of Striga emergence when Desmodium was established in the 1:3 sorghum-Desmodium ratio at seeding of sorghum. Total control of Striga was also achieved with the 1:1 sorghum-Desmodium ratio when Desmodium was transplanted 30 days before sorghum seeding. However, these two treatments also caused significant reductions in sorghum yield. In contrast, 100% Striga control and a dramatic increase in sorghum yield were achieved with 100 kg N ha^{-1} in the 1:1 sorghum-Desmodium intercrop. Compatibility of sorghum and Desmodium was evident at the 1:1 sorghum-Desmodium intercrop established at sorghum seeding. Overall, the Ethiopian cultivars Meko and Abshir showed better agronomic performance and higher tolerance to Striga than the South African cultivar PAN 8564. It is recommended that the N × Desmodium × sorghum interaction be investigated under field conditions.

水稻产量性状的遗传机制复杂，在低氮胁迫下进行QTL定位，可为产量性状遗传机制的解释、基因的精细定位和克隆提供参考价值，也可为筛选耐低氮水稻材料提供有价值的参考。本研究以66个水稻籼粳交片段导入系群体[粳稻(Oryza sativa ssp, japonica)楚粳12是供体亲本，籼稻(O. sativa ssp, indica)蜀恢527是受体亲本，采用回交和分子标记辅助选择相结合的方法构建]为定位群体，利用单标记作图法，对正常与低氮胁迫条件下水稻有效穗、单株产量、株高和生物学产量等性状进行QTL定位。共检测到24个QTLs，20个为新检测出的QTL，而qph-1、qpn-1、 qby-2、qby-4与前人研究结果相似，另外，qph-1a和qph-1b为在不同处理下均能影响株高的位点；生物学产量的QTL仅在低氮处理下被检测到；qpn-2b与qyd-2具有共同的连锁标记RM521；qpn-1b、qpn-2a、qpn-2b等加性效应值都小于1。结果表明，低氮胁迫明显影响单株有效穗、单株产量和生物学产量，且导入系群体检测微效QTL的能力较强。 | The genetic mechanism underlying yield traits is very complex, while QTL of rice yield traits which are uncovered in nitrogen starvation condition can provide a valuable reference to explain the genetic mechanism of yield traits, and facilitate fine QTL mapping and gene cloning, as well as screening of selective breeding of rice varieties tolerant to nitrogen starvation. In this study, 66 ILS population derived from the cross of Shuhui 527(Oryza. sativa ssp. indica) and Chujing 12(O. sativa ssp. japonica) which were served as the recurrent parent and donor parent; both marker-assisted selecting and high-generation backcrossing were used to detect QTL under the field experiment with normal and nitrogen starvation conditions by mapping with the single marker. A total of 24 QTLs were detected. Among of these QTLs, 20 QTLs were newly characterized, while qpn-1, qph-1, qby-4 and qby-2 were similar to the previous studies. qph-1a and qph-1b could affect the height of the site under the different treatments; we also found that both in the QTL of panicle number and grain yield per plant were linked with marker RM521 under nitrogen starvation condition; the additive effects of qpn-1b, qpn-2a and qpn-2b were less than 1. The results show that nitrogen starvation has strong negative effect on grain yield, panicle number, and biomass yield. Introgression lines population has strong ability for detecting micro effect QTL.

Malian farmers have been cultivating millet and sorghum for millennia, but they are slow to adopt and develop modern varieties because it is difficult to observe the difference in yields in their fields, given the challenging local growing conditions. Farmer participatory approaches are therefore recommended. This paper applies an instrumental variables method to survey data from Mali to evaluate the impacys of Diversity Field Fora, a type of farmer field school which aims to boost millet and sorghum yields by showing farmers how to manage diverse varieties. Impact indicators are expected and recalled millet and sorghum yields. the total number of unique attributes of millet and sorghum varieties stocked as seed, and the relative deprivation of the household farm with respect to these indicators. The findings suggest the project has had results at one of two sites where it has been implemented with the same local leadership and more intensively over a longer time frame.

To establish the organic cultivation of pepper using green manure crops, this work studied the growth characteristics and yield of green manure crops, mineral composition of green manure crops, mineral uptake in shoots of green manure crops, chemical composition in soil of green manure crops, and the growth characteristics and yield of pepper in vinyl house. Shoot dry weight of green manure crops was higher level in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. Also, the roots were spread deeply into soil in Sorghum bicolor and Sorghum. Density of root-knot nematodes in rhizosphere of green manure crops was significantly more decrease in Crotalaria juncea and Sorghum than in Glycine max and Sorghum bicolor. Total nitrogen and CaO content of green manure crops was significantly higher in Crotalaria juncea and Glycine max than in Sorghum bicolor and Sorghum. K₂O content was significantly higher in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. MgO content was not significant difference at all green manure crops. Cations content ratio of K₂O : CaO : MgO was 3.4 : 1.4 : 1. Total nitrogen uptake in shoots of green manure crops was high level in Glycine max, Sorghum bicolor and Sorghum compared with in Crotalaria juncea. K₂O and MgO uptake was significantly higher in Sorghum bicolor and Sorghum than in Crotalaria juncea and Glycine max. Value of pH in soil of green manure crops was more increase in Crotalaria juncea and Glycine max than in Sorghum bicolor, Sorghum and control, but after cultivation of pepper pH in soil was recovered with initial soil pH before seeding of green manure crops. EC value in control, green manure crops, and pepper cultivation decreased by 44%, 15~18%, and 38~61% level, respectively, compared with initial soil of green manure crops treatment. K content in soil of control, Crotalaria juncea and Glycine max cultivation was increased by 14%, but the K content in soil of Sorghum bicolor and Sorghum decreased by 24~38%. Cation exchange capacity (CEC) in soil of Crotalaria juncea and Sorghum bicolor decreased by 11%, but CEC in soil of Glycine max, Sorghum and control increased by 11%. Harvest fruit yield was higher in Crotalaria juncea, Glycine max, and Sorghum bicolor cultivation than in control and Sorghum.

It is well known that the parasitic weed Striga asiatica (L.) Kuntze can be suppressed by Striga-tolerant sorghum (Sorghum bicolor L. Moench) cultivars, Desmodium intortum (Mill.) Urb. (greanleaf desmodium), and by fertilization with nitrogen. The study objective was the assessment of Striga control provided by integration of Desmodium density, timing of sorghum-Desmodium intercrop establishment, and nitrogen fertilization. Growth responses and yield of three sorghum cultivars were measured in three pot experiments. A soil naturally infested with Striga was used, and that part of the soil which served as uninfested control was chemically sterilised. Striga numbers and growth were affected significantly by sorghum cultivars, sorghum-Desmodium intercrop ratios, timing of the sorghum-Desmodium association, as well as by their interactions. Desmodium caused 100% suppression of Striga emergence when Desmodium was established in the 1:3 sorghum-Desmodium ratio at seeding of sorghum. Total control of Striga was also achieved with the 1:1 sorghum-Desmodium ratio when Desmodium was transplanted 30 days before sorghum seeding. However, these two treatments also caused significant reductions in sorghum yield. In contrast, 100% Striga control and a dramatic increase in sorghum yield were achieved with 100 kg N ha −1 in the 1:1 sorghum-Desmodium intercrop. Compatibility of sorghum and Desmodium was evident at the 1:1 sorghum-Desmodium intercrop established at sorghum seeding. Overall, the Ethiopian cultivars Meko and Abshir showed better agronomic performance and higher tolerance to Striga than the South African cultivar PAN 8564. It is recommended that the N× Desmodium× sorghum interaction be investigated under field conditions. | The Ethiopian Institute of Agricultural Research (EIAR), Addis Ababa, Ethiopia; Tigray Agricultural Research Institute (TARI), Mekelle, Tigray, Ethiopia. | http://www.jarts.info | nf2012