دراسة تطور الإصابة بالتبقع السبتوري و علاقته ببعض الصفات الإنتاجية للقمح القاسي باستخدام بعض النماذج الرياضية

Abstract EN

The research was conducted at Settukhiris Research Station in Lattakia during 2016/2017 season to (i) study the effect of planting date and plant density on infection rate of wheat varieties Cham3 and Cham 9 with Septoria leaf spot, and its effects on agronomic traits, and (ii) determine the best mathematical models which represent infection rate development, and estimate the area under the disease progress curve.

Most studied traits varied significantly with the effect of studied treatments.

Plants at optimum planting date produced 38.4% more grain yield compared with the late planting date.

Cham 9 variety (moderately susceptible) was significantly superior compared with Cham 3 variety (susceptible) in most evaluated parameters.

In addition, the average infection rate of Cham 3 variety (55.3%) was higher than that of Cham 9 (30.3%).

Negative correlation was observed between leaf spot number and infection rate on the one hand and most other yield traits on the other hand.

The thousand kernel weight was the least affected parameter by the infection rate and leaf spot number, whereas spike length and grain number per spike were the most affected by the infection rate and leaf spot number.

The quadratic model was the best model to represent relationship between infection rate and time.

Monitoring the area under disease progress curve showed that the Septoria leaf spot progress was higher in Cham 3 than in Cham 9 by 2.11, 2.72 and 4.6 fold in the lower, medium and upper leaves, respectively.

Keywords: Septoria leaf spot, mathematical models, area under the disease progress curve; durum wheat