ITEMS FROM LEBANON

AMERICAN UNIVERSITY OF BEIRUT

FAFS, P.O. Box 11-236, Beirut, Lebanon.

 

Chromosome locSui-Kwong Yau and Jacqueline Pridham, and Martin Entz (University of Manitoba, Department of Plant Sciences, Winnipeg, Canada).

Root weight differences between Canadian wheat cultivars under organic farming management. [p. 79-80]

A field experiment comprising 15 bread wheat entries (four Canadian bread wheat cultivars and all their combinations) in four replicates was set up at a certified organic site near Carman in 2005 under organic management. The broad objectives of the experiment were to find out whether old cultivars would perform better than new cultivars under organic farming, and whether mixtures will perform better than pure lines. In this report, only results on root weight are presented.

Red Fife and Marquis were the two old cultivars used, and the two new cultivars were AC Barrie and BW297. Red Fife was first introduced in Manitoba in 1870. Marquis was developed later by Dr. Charles Saunders from a cross between Red Fife and an early ripening HRSW from India. AC Barrie became the most widely grown wheat cultivar just 2 years after certified seed sale in 1995. BW297, yet to be officially named, was developed by Proven Seed and its breeding partner AgriPro Wheat. BW297 has exhibited high yield and protein levels with a high level of Fusarium head blight and rust tolerance.

Roots were sampled after heading on 22 July, 2005. Two soil cores of 90-cm depth taken the day earlier showed that roots were no more than 20 cm deep. In order to take bigger samples in a shorter time, samples were collected manually with a circular root sampler instead of using the Giddings soil sampler. The root sampler was 15-cm tall with a diameter of 7 cm (lower side). A '21 x 21 cm' square covering two planted rows was sampled randomly within the area where shoot samples were harvested 3 days before. This meant that nine (3 x 3) scoops of soil, six from the two planted-rows and three from within the two planted-rows, were taken. Samples were stored at 3 C before washing and after washing before drying.

Cylindrical root washers, which remove the soil particles with water and compressed air coming out from the base of the cylinders, were used to clean the roots from the samples. After cleaning, seminal and basal roots were cut and collected manually. Roots coming out from the first node and from occasional weeds were not collected. Root dry weight was recorded after drying at 65C for 72 hr.

Analysis of variances showed that there were significant differences in root dry weight among entries (Table 1). One of the old cultivar, Red Fife, and one of the new cultivar, AC Berrie, had >30 % root dry weight than the other two cultivars: Marquis and BW297. Two mixtures (Red Fife with AC Berrie; and Red Fife, AC Berrie, with Marquis) gave the highest root dry weight (>30.0 g/aq m), and significantly higher than BW297, Marquis, the mixture of BW297, Marquis, and Red Fife, and the mixture of Marquis with Red Fife.

The unusual high rainfall of the growing season caused widespread flooding in Manitoba, and ditches needed to be dug around the experiment to lead water away from the plot. Thus, cultivar differences in root weight found in this study may not hold under normal or dry years.