Differences in temperature responses among phenological processes in diverse Ethiopian sorghum germplasm can affect their specific adaptation to environmental conditions.

BACKGROUND AND AIMS: Main shoot total leaf number (TLN) is a key determinant of plant leaf area and crop adaptation. Environmental factors other than photoperiod can affect TLN in sorghum, implying that leaf appearance rate (LAR) and development rate can differ in response to temperature. The objectives of this study were to determine (1) if temperature effects on TLN can be explained as a consequence of differences in temperature responses across phenological processes and (2) if genotypic differences in these responses can be linked to agroecological adaptation. METHODS: Nineteen sorghum genotypes were sown on 12 dates at two locations in Ethiopia with contrasting altitude, creating temperature differences independent of photoperiod. TLN and temperature were recorded in all experiments and LAR for six sowing dates. KEY RESULTS: Eleven of the genotypes showed a temperature effect on TLN, which was associated with a significantly higher base temperature (Tbase) for LAR than for pre-anthesis development rate (DR). In contrast, genotypes with no effect of temperature on TLN had similar Tbase for LAR and DR. Across genotypes, Tbase for LAR and DR were highly correlated, but genotypes with low Tbase had the greatest difference in Tbase between the two processes. Genotypic differences were associated with racial grouping. CONCLUSIONS: Genotypic and racial differences in responses of phenological processes to temperature, in particular in Tbase, can affect specific adaptation to agroecological zones, as these differences can affect TLN in response to temperature and hence canopy size and the duration of the pre-anthesis period. These can both affect the amount of water used and radiation intercepted pre-anthesis. A multi-disciplinary approach is required to identify genotype × environment × management combinations that can best capture the ensuing specific adaptation.

Genotypic variation in whole-plant transpiration efficiency in sorghum only partly aligns with variation in stomatal conductance.

Water scarcity can limit sorghum (Sorghum bicolor (L.) Moench) production in dryland agriculture, but increased whole-plant transpiration efficiency (TEwp, biomass production per unit of water transpired) can enhance grain yield in such conditions. The objectives of this study were to quantify variation in TEwp for 27 sorghum genotypes and explore the linkages of this variation to responses of the underpinning leaf-level processes to environmental conditions. Individual plants were grown in large lysimeters in two well-watered experiments. Whole-plant transpiration per unit of green leaf area (TGLA) was monitored continuously and stomatal conductance and maximum photosynthetic capacity were measured during sunny conditions on recently expanded leaves. Leaf chlorophyll measurements of the upper five leaves of the main shoot were conducted during early grain filling. TEwp was determined at harvest. The results showed that diurnal patterns in TGLA were determined by vapour pressure deficit (VPD) and by the response of whole-plant conductance to radiation and VPD. Significant genotypic variation in the response of TGLA to VPD occurred and was related to genotypic differences in stomatal conductance. However, variation in TGLA explained only part of the variation in TEwp, with some of the residual variation explained by leaf chlorophyll readings, which were a reflection of photosynthetic capacity. Genotypes with different genetic background often differed in TEwp, TGLA and leaf chlorophyll, indicating potential differences in photosynthetic capacity among these groups. Observed differences in TEwp and its component traits can affect adaptation to drought stress.

Interaction of microbiology and pathology in women undergoing investigations for infertility.

BACKGROUND: Cases of endometriosis with no tubal damage are associated with infertility, suggesting an immunological rather than mechanical barrier to reproduction. Laparoscopy and falloposcopy results of clinically asymptomatic women undergoing investigation of infertility were correlated with the outcomes of microbiological screening for Chlamydia trachomatis, Mycoplasma pneumoniae, Mycoplasma hominis, ureaplasma species, Neisseria gonorrhoeae, Neisseria meningitidis and Chlamydia pneumoniae. METHODS: A total of 44 women presenting to a hospital IVF service for laparoscopic or laparoscopic/falloposcopic investigation of infertility provided endocervical swabs, fallopian tube washings, and peripheral whole blood for analysis. RESULTS: Of these 44 women, 15.9% (7) showed evidence of C. trachomatis infection as detected by either PCR or EIA serology. Of these 7 women, 5 (71%) had no or mild endometriosis and 2 (29%) had moderate or severe endometriosis. Of the remaining 37 women who showed no evidence of chlamydial infection, 15 (40.5%) had no or mild endometriosis. CONCLUSION: Women with infertility, but without severe endometriosis at laparoscopy, showed a trend towards tubal damage and a higher rate of previous C. trachomatis infection. Although not statistically significant, this trend would suggest that, where moderate to severe tubal damage is found to be the primary cause of infertility, C. trachomatis infection could be a likely cause for such tubal damage.