Production of tillers and their subsequent survival are important events in growth and development of barley ( Hordeum vulgare L.) that affect the number of spikes produced per unit land area. Studies were conducted at St. Paul and Crookston, MN to evaluate tiller production, tiller mortality, and yield of 10 barley genotypes with different tillering capacities. In addition, these studies evaluated the influence of row spacing and seeding rate on tillering. The genotypes differed significantly in shoot and spike number. Shoot number for the highest tillering genotype was 42 to 71% greater than for the lowest, depending on the study, but the genotypes ranked consistently over years and locations. The high tillering genotypes tended to form tillers more frequently at the coleoptile node, in the axil of the third leaf, and from the primary tiller in the axil of the first leaf on the main shoot. In general, absolute shoot mortality (difference between maximum shoot number and spike number) was higher in the high tillering genotypes. Genotype M72‐269 was an exception to this generalization in having high shoot number and low shoot mortality. Row spacings of 7.5 and 15 cm had more shoots per unit area than the 30 cm spacing. However, narrower rows also had higher shoot mortality which led to similar spike numbers for the three row spacings. Higher seeding rates of 101 and 134 kg ha ‐1 increased shoot number and spike number compared to the 67 kg ha ‐1 rate. Changes in row spacing and seeding rate did not differentially affect shoot production or absolute shoot mortality among the genotypes. Grain yields of both low and high tillering genotypes were as high or higher than those of intermediate tillering cultivars. The extremely high and low tillering genotypes were not consistent in their yield performance at Crookston, suggesting a possible association between tillering capacity and yield stability. Small stem diameter and a tendency to lodge were characteristic of the high tillering genotypes. Identification of apparent genetic diversity for tiller mortality provides material for further study of the relationship between tiller mortality and yield.
Abstract A set of plots were established at 8 different locations representative of present and recent past sunflower production in MN. Individual plots were 4 rows × 35 ft in 30 inch rows. The same 11 treatments and 4 replicates were used at each location and arranged in a randomized complete block design with different randomization at each location. Soil types varied from clay at Crookston to sandy loam at Oklee. Furadan 4F and 15G were applied in a 4 inch band on the row at, or as soon after, planting as possible and incorporated. Foliar applications of Furadan 4F and Pydrin 2.4E were broadcast at the appropriate plant stage. Foliar applications were made with a hand held CO2 sprayer using about 20 gal of total material per acre applied at 40 lb psi. Defoliation readings and stem infestations were collected during the growing season. Heads were taken by hand on the center two rows, dried, threshed and yields of clean seed recorded. Yields were analyzed by location and together and are so reported.
Planting soybean [( Glycine max (L.) Merr.] into Fe chlorosis‐prone soils where soybean has seldom, if ever, been grown may require special precautions to establish effective Bradyrhizonium japonicum populations, while simultaneously providing adequate levels of N for the current crop. However, adding fertilizer N likely will increase rhizosphere pH and [ OH − ] and, thus, promote Fe deficiency. Our objective was to determine whether varieties (Vs) that differed in Fe efficiency also differed in their response to added N fertilizer when grown on chlorosis‐prone soils. Six varieties (2 Fe efficient, 2 moderately Fe efficient, and 2 Fe inefficient) and six rates of fertilizer N (0, 34, 68, 102, 136, and 170 kg N ha −1 ) were evaluated during 2003, 2004, and 2005 using soils belonging to the soil subgroup, Aeric Calciaquolls. Growing conditions in 2004 were colder and wetter than either 2003 or 2005, whereas DTPA‐extractable Fe was twofold greater in 2004. Extractable Fe did not necessarily reflect available Fe as relative chlorophyll concentrations (SPAD readings), seed number and weight, and grain yield were all significantly ( P < 0.05) less in 2004. Nodulation decreased linearly in response to added N for all varieties, regardless of their Fe efficiency characterization or yearly growing conditions. SPAD readings differed markedly among Vs (22.1–33.8), but showed little response to increasing nitrogen rates (NR) (27.8–30.7). Plant height, seed number, and grain yield all decreased linearly in response to increasing NRs for Fe‐inefficient Vs, whereas these responses in Fe‐efficient and moderately efficient Vs changed little as NR increased. Our results strongly suggest that N should not be applied when Fe‐inefficient Vs are grown on Fe chlorosis‐prone soils.
‘RB07’ (Reg. No. CV‐1028, PI 652930) hard red spring wheat ( Triticum aestivum L.) was developed by the University of Minnesota Agricultural Experiment Station and released in 2007. RB07 was tested as MN99436‐6 in statewide yield trials from 2003 to 2006 and in the Uniform Hard Red Spring Wheat Regional Nursery in 2003 and 2004. RB07 was released based on its high and consistent grain yield, earliness, disease resistance and good grain end‐use quality. It is well adapted to hard red spring wheat–growing regions in Minnesota, North Dakota, and South Dakota.
Abstract Two sets of plots were established, one at Grand Forks, ND and one at Crookston, MN. The same 10 treatments were included at each location but randomization was changed. Individual plots were 4 rows X 30 ft in length with a 6 ft aisle between replications. The experimental design was a randomized complete block. Temik granules were applied at planting and foliars on the dates indicated. Non-threshold plots were treated 1 Jul. “Threshold” plots were not initially treated until 10% defoliation had occurred which was 10 Jul. All foliar treatments thereafter for threshold and non-threshold plots were applied the same day (19, 31 Jul and 14 Aug). All plots were treated 3 times with the fungicide Bravo 500. The % defoliation was estimated by 3 people and averaged. Yields were taken from the center two rows of each plot, graded #1 or #2, weighed and recorded. The yields at the two locations were averaged.
‘Rasmusson’ (Reg. No. CV‐345, PI 658495) is a spring, six‐rowed, malting barley ( Hordeum vulgare L.) released by the Minnesota Agricultural Experiment Station in January 2008. It was named after Donald Rasmusson, who worked as a barley breeder at the University of Minnesota from 1958 to 2000. Rasmusson has the pedigree M95/‘Lacey’ and is the product of advanced cycle breeding derived from crosses among elite breeding lines within the University of Minnesota breeding program. Rasmusson was released based on its superior yield performance across the Upper Midwest of the United States and surrounding regions in Canada and favorable malting quality, in particular, high malt extract. Rasmusson is resistant to spot blotch [caused by Cochliobolus sativus (Ito and Kuribayashi) Drechs. ex Dastur] and the prevalent races of stem rust (caused by Puccinia graminis Pers.: Pers. f. sp. tritici Erikss. & E. Henn).
Abstract The cost of hybrid sunflower ( Helianthus annuus L.) seed provides an incentive for reducing planting rates which, in turn, reduce plant populations. This research was undertaken to determine minimum populations needed for maximum yield and their effect on seed quality and head drying. Populations of oilseed and nonoilseed cultivars of 17, 25, 37, 49, and 62 thousand plants/ha were established at six locations in Minnesota. Soils were Typic Haplaquolls, Aeric Calciaquolls, Typic Eutroboralf and Udorthentic Haploborolls. Both oilseed and nonoilseed cultivars required the same populations for maximum yield. Minimum populations needed for maximum yield varied from 25 to 62 thousand plants/ha among locations. Differences in optimum plant populations among locations were attributed to soil, rain, and temperature. Yields were not depressed by populations up to 62 thousand. Optimum population for oilseed and small‐nonoilseed cultivars was that which gave maximum yield because seed quality factors of test weight and/or oil percentage increased with population. Optimum population for large‐nonoilseed cultivars was often less than that giving highest yield because the percentage of large seeds decreased with increasing population. As plant populations increased from 17 to 62 thousand plants/ha, head moisture percentages decreased from 68 to 50% at early harvest and from 43 to 20% at later harvest. Preharvest desiccant sprays reduced head moisture but did not alter the relationship between increasing population and decreasing head moisture. Increasing row spacing to conserve soil moisture between rows did not increase yield on a sandy soil.
