Relationship between epistasis and aggressiveness in resistance of pepper (Capsicum annuum L.) to Phytophthora nicotianae

This study evaluated the types of gene action governing the inheritance of resistance to Phytophthora nicotianae necrosis in populations derived from two crosses involving two susceptible (Beldi and Nabeul II) and one resistant (CM334) cultivars of pepper (Capsicum annuum L.). Populations, composed of Pr, Ps, F1 , F 2 , BC 1 Pr, and BC 1 Ps generations, were inoculated with six P. nicotianae isolates. Generation means analysis indicated that an additive-dominance model was appropriate for P. nicotianae isolates Pn Ko1 , Pn Ko2 and Pn Kr1 , which showed low aggressiveness in the two crosses. For the more aggressive isolates Pn Bz1 , Pn Bz2 and Pn Kr2 , epistasis was an integral component of resistance in the two crosses. The presence of epistasis in the resistance of pepper to P. nicotianae was dependent on the level of aggressiveness of the isolates. Selection in pepper with less aggressive isolates was efficient, but not with more aggressive isolates; on the other hand, selection with more aggressive isolates was more stable. The minimum number of genes controlling resistance was estimated at up to 2.71. In the majority of cases, the additive variance was significant and greater than the environmental and dominance variance

A Novel Morbidity Prediction Model for Head and Neck Oncosurgery

The purpose of the study was to construct and validate a risk model to predict morbidity in head and neck oncosurgeries. Potential risk factors of 300 surgically treated head and neck cancer patients like age, sex, tumor site, TNM stage, duration of surgery, adjunctive treatment, comorbidities and alcohol and tobacco usage were analyzed. Postoperative complications were noted. We developed a logistic model to predict the probability of patients developing morbidity based on the statistically significant variables-duration of surgery, preoperative radiation and hypertension. The validity of the test was assessed by the c-index which were 0.79 (95% C.I 0.71–0.87) for the study set (250 patients) and 0.86(95% C.I 0.73–0.90) for the test set (50 patients). The correlation of observed to expected morbidity was 0.709 (P < 0.0001). We validated a risk model and constructed a simple chart that provides us an assessment of the risk of a patient of developing morbidity