Volume 39, Number 8 | MARCH 18, 2013
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PRACTICAL PRODUCTION TIPS FOR THE PRAIRIE FARMER
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A solid step in durum breeding AAC Raymore is the first solid-stemmed variety of amber durum to be registered in Canada BY SARAH WEIGUM
A
new durum variety raises the bar for Prairie farmers and makes life a lot more challenging for one of their common nemeses — sawflies. AAC Raymore, released by SeCan to all its member seed growers in February 2013, is an amber durum (CWAD) with similar yield, quality and agronomic traits to AC Strongfield, but with the added bonus of a solid stem, which makes it a far less hospitable host to sawfly than traditional hollow-stem varieties.
AAC RAYMORE AAC Raymore was developed by Agriculture and Agri-Food Canada’s Danny Singh, along with fellow plant breeders who have been working on improving durum yield and agronomics for many years at the Swift Current, Sask., research station. Other solid-stem varieties have been developed in the past, but they either did not meet the quality specifications for CWAD or had agronomic weaknesses like poor straw strength. “In addition to protection against wheat stem sawfly, AAC Raymore has a competitive overall package for grain yield, protein and quality acceptable for CWAD,” says Singh “It is a large seeded cultivar and has good resistance to the majority of diseases, including stripe rust and common root rot.” Solid-stem varieties of wheat like AC Lillian have been available for several years, gaining popularity due to their sawfly tolerance, but AAC Raymore is the first solid-stem variety of CWAD to be registered in Canada. According to Scott Meers, insect management specialist with Alberta Agriculture and Rural Development, the solid stem reduces the sawfly population in two ways. “The solidness in the stem increases the mortality of the sawfly larvae and the sawfly that
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do manage to get through and cut the wheat actually lay fewer eggs the next year,” says Meers. A study quoted by Saskatchewan Agriculture in 2006 found larval mortality to be 28 per cent in hollow stems and about 67 per cent in solid stems.
SAWFLIES AND STEMS Sawflies, which are not true flies but actually relatives of bees, wasps and ants, typically favour the hot, dry climate that is characteristic of traditional durumgrowing areas, although they have been found in other areas of the Prairies as well. Female sawflies cut into stems of wheat and durum with a saw-like organ and lay their eggs there in June and July. When the larvae hatch they move through the stem, eventually cutting a groove around the edge of the stem near ground level. Wind or rain can knock over the weakened stem, making it difficult to pick the heads off the ground at harvest time. Sawfly larvae also contribute to yield loss. They feed on the nutrient-carrying phloem tissue inside the stem, leading to fewer or more shrivelled seeds per head. “In a hollow variety [the larvae] can get to the cells inside the stem that are very easy for the young sawfly to eat,” says Meers. “In the solid stem the eggs are laid right inside the stem and the young sawfly can’t get outside of the solid tissue.”
PHOTOS: SECAN
Danny Singh, AAFC plant breeder, in a plot of AAC Raymore durum.
SAWFLY RESISTANCE Jim Downey, SeCan’s research and development manager, is optimistic about the potential of this new variety to resist sawfly. “Raymore has an exceptionally solid stem. It expresses the pith to fill the stem from the ground to the head,” said Downey. In contrast, he said
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DT818, now registered as AAC Raymore, next to a plot of AC Strongfield durum
In This Issue
Wheat & Chaff ..................
2
Features ............................
5
Crop Advisor’s Casebook
10
Columns ........................... 28 Machinery & Shop ............ 34 Cattleman’s Corner .......... 40
Ascochyta in chickpeas MELANIE EPP PAGE 6
Spectruckular Special SCOTT GARVEY PAGE 34
FarmLife ............................ 45