Soft rot caused by Pectobacterium carotovorum (Pc) is a devastating disease of Brassica rapa, causing substantial reductions in crop yield and quality.  Identifying genes related to soft rot resistance is the key to solving this problem.  To characterize soft rot resistance, we screened a soft rot-susceptible Chinese cabbage (A03), a resistant pakchoi (‘Huaguan’), and a resistant mutant (sr).  An F₂ population was generated by crossing susceptible Chinese cabbage A03 and resistant pakchoi ‘Huaguan’ to identify quantitative trait loci (QTLs) that confer soft rot resistance.  A high-density genetic map was constructed and the three QTLs identified contain 166 genes.  Based on available transcriptome data, we analyzed the expression of the 166 genes during an important defense regulatory period in Pc infection in both A03 and the resistant mutant sr.  Among the 166 genes, six candidate genes were related to the soft rot defense response in B. rapa.  TIFY10B (JAZ2, BraA07g038660.3C) was located in the major soft rot resistance QTL, DRQTL-3 on A07, and we speculate that this gene may play an important role in the defense mechanism against soft rot in B. rapa.  This study lays the foundation for further investigations on the mechanism of soft rot resistance in B. rapa crops.

    Covered smut, which is caused by Ustilago hordei (Pers.) Lagerh., is one of the most damaging diseases of highland barley (Hordeum vulgare Linn. var. nudum Hook. f) in Tibetan areas of China. To understand the molecular diversity of U. hordei, a total of 27 isolates, which were collected from highland barley plants from Tibet, Sichuan, Qinghai, and Gansu provinces/autonomous region, were analyzed using random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers. Among the 100 RAPD primers used, 24 primers exhibited polymorphism. A total of 111 fragments were amplified, of which 103 were polymorphic with a polymorphic rate of 92.79%. The average observed number of alleles (Na), effective number of alleles (Ne), Nei’s genetic diversity (H), Shannon’s information index (I) and polymorphism information content (PIC) value in the RAPD markers were 1.9279, 1.5016, 0.2974, 0.4503 and 0.6428, respectively. For the SSR markers, 40 of the 111 primer pairs exhibited polymorphism and provided a total of 119 bands, of which 109 were polymorphic and accounted for 91.60% of the total bands. The Na, Ne, H, I and PIC values of the SSR markers were 1.9160, 1.4639, 0.2757, 0.4211 and 0.4340, respectively. The similarity coefficients ranged from 0.4957 to 0.9261 with an average of 0.7028 among all the 27 isolates used. The dendrogram, which was developed based on the RAPD and SSR combined marker dataset showed that the 27 U. hordei isolates were divided into 3 clusters at similarity coefficient of 0.7314. We determined that RAPD and SSR markers can be successfully used to assess the genetic variation among U. hordei isolates. The RAPD markers revealed higher levels of genetic polymorphism than did the SSR markers in this study. There existed a moderate genetic difference among isolates. The molecular variation and differentiation was somewhat associated with geographical origin but not for all of the isolates.

Agriculture is facing great challenge in meeting global food security and is expected to face even greater challenge under climate change. The overall goal of this paper is to examine how finance can be used to achieve the joint objectives of development, mitigation of and adaptation to climate change in agriculture in developing world based on literature review. The results show that agriculture is much under invested and foreign aid also has not increased appropriately to assist developing countries to maintain sustainable agriculture under climate change. There are a wide range of areas in mitigation of and adaptation to climate change that need substantial investment. Major areas and successful cases mitigation of and adaptation to climate change in agriculture that have worked in developing countries are examined. A list of areas that have worked, could work and be scaled up or transferred is identified and discussed. This study concludes that mainstreaming agricultural mitigation and adaptation into agricultural development programs, enhancing local capacity, and considering different stakeholders’ needs are major experiences for successfully financing sustainable agriculture under climate change.

Under climate change, rising frequency and serious extreme weather events have challenged agricultural production. Designing appropriate adaptation measures to the extreme weather events require rigorous and empirical analysis. The overall goals of this study are to understand physical adaptation measures taken by farmers and the impacts of household and community assets on farmers’ adaptation when they face drought. The analyses are based on a unique data set collected from a household survey in three provinces in China. The survey results show that though not common on annual basis, some farmers did use physical adaptation measures to fight drought. Regression analysis reveals that both household and community assets significantly affect farmers’ adaptation behaviors. Improving households’ social capital and wealth, communities’ network and access to government’s anti-drought service can facilitate farmers’ adaptation to drought. Results indicate that community’s irrigation infrastructure and physical adaptation taken by farmers can substitute each other. Further analysis shows that the households taking adaptation measures have higher crop yields than those without taking these measures. The paper concludes with several policy implications.

The matrix metalloproteinase 23 (MMP-23), which might play a role in ovulation in mammals, was one of the promising candidate genes for litter size traits in pigs. In the present research, partial sequence of porcine MMP-23 (pMMP-23) gene, including exons 2-8 (GenBank: EU360790), was obtained. Real-time PCR analysis revealed that pMMP-23 gene was highly expressed in ovary. PCR-Sau3A I-RFLP and PCR-Acc II-RFLP assay were established to detect a C/T mutation in exon 3 (EU360790: g. 269C>T) and an A/G mutation in exon 4 (EU360790: g. 505A>G), respectively. Association study for these two SNPs with litter size was assessed in three independent populations (Minzhu, Landrace I and Landrace II). Statistical analysis demonstrated that for second and subsequent litters, TT sows produced more TNB than CC pigs in Landrace breed (P<0.05) at g. 269C>T locus, and the additive effect was significant (P<0.05); GG sows produced more TNB and NBA than AA pigs in Minzhu (P<0.01) and Landrace breeds (P<0.05) at g. 505A>G locus, and the additive effect was significant (P<0.01 or P<0.05). Our study suggested that the pMMP-23 gene might be a novel candidate gene for litter size traits, and g. 505A>G locus might be a useful molecular marker for marker assisted selection (MAS).

The carbon (C), nitrogen (N) and phosphorus (P) variations of a temperate wetland soil under continuous cultivation for 40 yr were determined and evaluated in the Sanjiang Plain, Northeast China. The results showed that the soil organic carbon (SOC) and total nitrogen (TN) contents in each soil layer decreased sharply after cultivation for 2-3 yr, and exhibited minor differences after cultivation for 11 yr, which showed an exponential decline curve with the increase of cultivation years. The reduction rates of carbon and nitrogen reserves were 14.79% and 28.53% yr-1 at the initial reclamation stages of 2-3 yr and then decreased to 2.02-3.08% yr-1 and 1.98-2.93% yr-1 after cultivation for 20 yr, respectively. Soil total phosphorus (TP) reserves decreased within cultivation for 5 yr, and then gradually restored to the initial level after cultivation for 17 yr. Both SOC and TN could be restored slightly when the farmland was left fallow for 8 yr after reclamation for 11 yr, whereas TP had no significant difference. These results demonstrated that wetland cultivation was one of the most important factors influencing on the nutrient fate and reserves in soil, which could lead to the rapid nutrient release and slow restoration through abandon cultivation, therefore protective cultivation techniques preventing nutrients from loss should be immediately established after wetland reclamation.