2 results
Trichome numbers in naked-oat cultivars
- A.-M. KIRKKARI, P. PELTONEN-SAINIO, L. JAUHIAINEN
-
- Journal:
- The Journal of Agricultural Science / Volume 147 / Issue 1 / February 2009
- Published online by Cambridge University Press:
- 08 December 2008, pp. 63-69
-
- Article
- Export citation
-
The oat kernel, caryopsis or groat, is generally covered with fine silky hairs termed trichomes. The trichomes of naked oat are partly lost during threshing and handling of grains when the lemma and palea are removed and the surface of the grain is exposed. Trichomes can cause itchiness and more serious reactions in those handling the grains. Trichomes also accumulate and form fine dust and can block up machinery. Trichomes are clearly problematic and growers of naked oat are eager to have oat cultivars with reduced numbers of trichomes. Experiments compared the differences in trichome numbers of naked-oat cultivars and threshing settings. The cultivars differed considerably in pubescence. Cultivars Lisbeth and NK 00117 had most trichomes and cv. Bullion the fewest. Completely bare or polished grains were not observed. Pubescence was not associated with grain weight or test weight. However, grains from the lowermost spikelets of the panicle had fewer trichomes than those from the uppermost spikelets. For cv. Bullion, some threshing settings, including increased cylinder speed, slightly increased grain polishing such that grains had some areas completely free of trichomes. Reduction of the concave clearance in the combine harvester had a similar effect. However, threshing settings did not affect the trichomes of cv. Lisbeth. Adjusting threshing machinery settings was generally not an efficient means of solving the problems associated with naked-oat trichomes, but cultivar differences existed and further efforts in breeding to reduce trichome numbers are required.
Germination and grain vigour of naked oat in response to grain moisture at harvest
- P. PELTONEN-SAINIO, S. MUURINEN, M. VILPPU, A. RAJALA, F. GATES, A.-M. KIRKKARI
-
- Journal:
- The Journal of Agricultural Science / Volume 137 / Issue 2 / September 2001
- Published online by Cambridge University Press:
- 24 October 2001, pp. 147-156
-
- Article
- Export citation
-
Naked oat grain, which is free from lemma and palea, has high nutritional quality, but the unprotected grain is prone to mechanical damages caused by combine harvesting. Naked oats were grown for 3 years in southern Finland, at Viikki Experimental Farm, University of Helsinki (60° 13′N) to produce seed material for laboratory tests that evaluated: (1) genotypic differences of naked oat in sensitivity to damage during harvesting at grain moisture varying from c. 10% up to 50%, (2) the effect of mechanical damage on germination and grain vigour, and (3) grain characteristics contributing to susceptibility to reduced grain viability. In 1997, one naked (Rhiannon) and husked oat cultivar (Salo) were harvested, and in 1998–1999 additional four naked cultivars (Bullion, Lisbeth, Neon, SW 95926) were included. One large plot (14 m×10 m) was sown per cultivar. Two sowing times were used. Fully ripened grains were combine harvested on several occasions for each plot to obtain differences in grain moisture at harvest. Simultaneously, panicle samples were collected, dried and threshed by hand (controls). Grain moisture at each sampling and harvesting was monitored. About 3 months after harvesting, germination tests on blotting paper were carried out. Proportions of normally developed seedlings, seedlings lacking either radicle or hypocotyl, damaged coleoptiles, dead grains and lethally fungus-infected grains were recorded from combine harvested and hand threshed samples on different cultivars and harvest moistures. Tests on seedling elongation, seedling emergence through sand (2 cm and 5 cm depth), and ion leakage were applied to evaluate grain vigour. Groat weight, diameter, length, roundness, hardness and protrusion of embryo were determined.
Our results indicated that naked cultivars were far more prone to mechanical damages than husked Salo, but differences among naked cultivars in susceptibility occurred. When targeting germination of [ges ] 75%, grain moisture at harvest should not exceed 19–26% depending on cultivar. Abnormal seedlings appeared irrespective of grain moisture at harvest, but the higher the grain moisture, more dead grains were found in harvested grains after storage. Seed vigour did not alter parallel to germination ability. High proportion of small grains in harvested yield and softer groats contributed to decreased sensitivity to mechanical damages.