The present work investigated the efficiency of leaf reflectance indices in the identification of Capsicum annuum L. var. annuum resistant to anthracnose in the fruit. Twenty-five F5:6 families originating from contrasting parents were assessed;the parents were accession UENF 2285 (susceptible to anthracnose) and accession UENF 1381, a hot pepper resistant to anthracnose in the fruit. The experiment was carried out in an experimental field in Campos dos Goytacazes, Rio de Janeiro, Brazil, between May and October of 2021. The treatments were arranged in a randomized block design, with three replications and five plants per plot. Fifteen LRIs were estimated using a CI-710 portable mini leaf spectrometer. The assessments covered all plant growth after flowering, and a total of six assessments were performed at 15-days intervals, beginning at 35 and ending 120 days after flowering (DAFs). Analysis of variance in a split-plot scheme was performed, as were tests of mean groupings and principal components analysis (PCA). The best period for evaluating leaf reflectance indices in C. annuum var. annuum is 120 days after flowering. The leaf reflectance indices PRI, CNDVI and Ctr2 stood out as effective in distinguishing between resistant and susceptible genotypes.
Rosimara Barboza BispoMaria Do Socorro Bezerra AraújoAntônio André da Silva AlencarCláudia Pombo SudréRosana Rodrigues
The present study focused on evaluating the agronomic performance, stability, and anthracnose resistance of common bean lines derived through Marker-Assisted Backcrossing in Uganda. Eight marker-assisted selection (MAS) backcross-derived bush bean lines with red seed types, alongside two checks, were evaluated in a randomized complete block design replicated two times in five locations for three consecutive crop-growing seasons in 2021 and 2022. The study aimed to identify lines with both high stable yields and enhanced resistance to anthracnose disease for potential release and utilization in future bean varietal development in Uganda. Agronomic traits, including days to 50% flowering, days to 90% physiological maturity, seed yield, seed yield components, and anthracnose disease reaction under natural infestation were assessed. The response to anthracnose disease was further assessed using six isolates of Colletotrichum lindemuthianum representing six different races. Results indicated that the agronomic performances of the MAS backcross-derived bush bean lines were statistically comparable to the recurrent parent NABE14. Specifically, six lines exhibited statistically equal to or higher performance than NABE14 in terms of seed yield, total number of seeds and number of pods per plant. The combined analysis of variance for seed yield showed significant (p Co-42 and Co-5 anthracnose resistance genes in the derived line. In conclusion, UGKT-B157-4, identified as the best-performing and stable genotype, demonstrates promise for release and use in future bean varietal development in Uganda, offering a combination of high yields and enhanced anthracnose disease resistance. The study provides valuable insights into the potential of Marker-Assisted Backcrossing in improving common bean varieties in the region.
Stanley T. NkaluboAnnet NamayanjaAnnet NamusokeJane MukabarangaNampijja ShakirahAllan NkuboyePaul GeptsWakjira Tesfahun Jebesa
Background:Plant phyllosphere microbes are important for the host plant's protection.Plant growth-promoting rhizobacteria(PGPR)and Trichoderma are common biocontrol agents(BCAs)for disease management.Pathogens and BCAs can change the rhizosphere microbial composition;however,the effect of PGPR or Trichoderma on plant phyllosphere microbes,particularly for mesocosms involving the interaction between pathogens and BCAs,is not well known.Methods:High-throughput sequencing was used to identify the phyllosphere bacterial community of common vetch interacting with Colletotrichum spinaciae,two PGPRs(Bacillus subtilis and Bacillus licheniformis),and Trichoderma longibrachiatum.We evaluated anthracnose severity,phyllosphere bacteria diversity and composition,and the relationship between the activities of plant defense enzymes and hormonal molecules in plants treated with individual and combined inoculations of PGPRs,Trichoderma,and C.spinaciae.Results:PGPR or Trichoderma alone reduced disease severity.Trichoderma reduced the salicylic acid content,PGPR increased the catalase activity in plants,and co-inoculation of PGPR and Trichoderma decreased the salicylic acid content.Inoculation of PGPR and Trichoderma individually or in combination changed the disease-associated phyllosphere bacteria,and this effect was related to plant defense enzymes and hormonal molecules.Conclusions:We suggest that the plant defense response induced by PGPR and Trichoderma results in the enrichment of a fraction of favorable chloroplastic bacteria,which facilitates plant defense against diseases.