Little yield improvement of soft red winter wheat (Triticum aestivumL. em Thell.) has occurred in Pennsylvania and other northeastern states during the past 30 years while wheat yields have nearly doubled in several European countries. In England and Wales, about 40% of this increase is attributed to improved management. Our objective was to determine the potential yield increases under Pennsylvania conditions from near optimum combinations of seeding rate, row spacing, seeding depth, and N fertilization in the spring. Field experiments were conducted at a total of 15 locations during 1981 and 1982 on either Typic or Ultic Hapludalf soils. The cv. Roland was used, and treatments were seeding rates of 100,168, or 235 kg ha−1, 19 or 38 mm seeding depths, 127 or 178 mm row spacing, and 0, 34, 67, or 100 kg ha−1of N fertilizer topdressed in March at growth stage 3 (Feekes scale). Grain yields ranged from 2642 to 5342 kg ha−1and averaged 4134 kg ha−1. Yields increased in 14 of 15 environments when row spacing was decreased to 127 mm. The average yield increase from using narrow row spacing was about 7.5%. The effect of spring N fertilization was variable but grain yields and test weights were decreased at N levels above 34 kg ha−1. Seeding rate responses also were variable, but averaged over all environments, yields were not increased by using more seed than 168 kg ha−1. The greatest response to seeding rate occurred following late planting. At five of six locations where seeding depth effect was significant, yields were greatest from deep seeding. The best combination of treatments was 168 kg ha−1of seed, 38 mm seeding depth, 127 mm row spacing, and 34 kg ha−1of N. The average yield for this combination was 4630 kg ha−1which is more than double the state average yield.

Breeding schemes to improve alfalfa (Medicago sativa L.) forage quality based on total herbage chemical composition can result in altered morphology. Additionally, cell‐wall composition of plant parts also may be altered. This study investigated the effects of divergent selection for lignin concentration in total herbage of alfalfa on concentration of cell‐wall components and digestibility of stems. Two groups of alfalfa previously derived from herbage‐based selection were studied. Group 1 consisted of six two‐parent Syn‐2 lines randomly selected from ‘Saranac‐AR’ for high (HL) or low (LL) acid‐detergent lignin (ADL) concentration in the total herbage. Group 2 had 11 HL and 13 LL lines produced from crossing pairs of parents of the Group 1 lines. Neutral‐detergent fiber (NDF) concentration in stem bases was 4 and 3% greater in HL lines than in LL lines in Group 1 and 2, respectively. Likewise, herbage NDF concentration was 8% greater in HL than in LL lines of Group 1 and 4% greater in Group 2. There were no differences between divergent lines in NDF concentration of stem tops. Lignin concentration in cell walls of Group 1 was 8 and 6% greater in LL lines than in HL lines in stem tops and stem bases, respectively. In Group 2, the LL lines had 2% greater cell‐wall lignin concentration than HL lines in both stem fractions. Total‐herbage NDF concentration correlated more closely with leaf‐to‐stem ratio of entire plants (r = − 0.96 and −0.78 for Group 1 and 2, respectively) than with stem length and maturity. Thus, herbage‐based selection for improved nutritive quality of alfalfa results in complex changes in stem cellwall component concentrations in addition to large morphological changes.

The isolation and analysis of cell‐wall types (CWT) such as parenchyma and sclerenchyma provide a means of understanding the complex chemistry of forage fiber. Our objective was to compare the composition of purenchyma and sclerenchyma cell walls of field grown orchard grass (Dactylis glomerata L.) and switch grass (Panicum virgatum L.) harvested at four stages of plant maturity. Leaf blades, leaf sheaths, and stems were analyzed for fiber constituents. Parenchyma and sclerenchyma cell walls were mechanically isolated from plant parts and analyzed for neutral sugars, alkali‐labile phenolic acids, and lignin. Neutral‐detergent fiber (NDF), hemicellulose, cellulose, and lignin concentrations differed (P < 0.05) between plant parts. Parenchyma cell walls differed widely in composition, with urabinose ranging from 25 to 81 g kg−1; xylose, 92 to 282 g kg−1; glucose, 410 to 634 g kg−1; p‐coumaric acid, 1 to 19 g kg−1; ferulic acid, 2 to 10 g kg−1; and lignin, 38 to 104 g kg−1. Sclerenchyma cell walls were more uniform in composition, with arabinose ranging from 10 to 30 g kg−1; xylose, 204 to 330 g kg−1; glucose, 411 to 533 g kg−l; p‐conmaric acid, 5 to 16 g kg−1; ferulic acid, 3 to 9 g kg−1; and lignin, 51 to 99 g kg−1. In most cases, the ratios of xylose to urabinose and p‐coumaric acid to ferulic acid were lower (P < 0.05) in purenchyma compared with sclerenchyma, and in leaf blade or leaf sheath CWT compared with those of the stem. These results suggest that the chemistry of CWT is complex and that studies of heterogenous preparations such as NDF are confounded by the chemical diversity of CWT contained in forages.

mates of root size only at certain times during the summer. Neither method would be useful if a large portion of the root was naturally severed. AbstractElectrical capacitance and root diameter techniques for estimating root dry weight were evaluated in one test with red clover plants grown on slant-boards in plant growth chambers for 37-77 d, and in six tests with alfalfa grown in the field for 55-165 d. Root dry weights of red clover were estimated satisfactorily with regression equations from both diameter (R^ = 90%) and capacitance (72^ = 76%) measurements. Root dry weights of alfalfa were estimated satisfactorily throughout the entire season from diameter values (R^ from 51 to 92%). Alfalfa root weight was significantly (f <0 05) related to capacitance values at the beginning and at the end ofthe season but not at mid-season. Electrical capacitance measurements were similar for intact root systems and roots severed 4 cm below the crown in separate experiments with red clover and with alfalfa. The root diameter technique provided an accurate, rapid and inexpensive method of estimating root size throughout the first season of growth. The root capacitance method provided satisfactory estiConlribulion No. 8103 from the U.S. Regional Pasture

Quantitative genetic parameters were estimated for first harvest yield, acid detergent fiber (ADF), acid detergent lignin, in vitro dry matter disappearance (IVDMD), and protein in ‘Saranac’ and ‘MSA‐C4’ alfalfa (Medicago sativa L.). Neutral detergent fiber (NDF) and in vitro cell wall digestibility (IVCWD) were determined in Saranac. Genotypic, phenotypic, and environmental correlations among each of the characters and with concentrations of 11 mineral elements were computed for Saranac. All estimates were obtained from analysis of a series of four, five‐parent diallel crosses and their parents in each cultivar.Relatively large estimates of heritability were obtained for lignin (43.8%) and protein (64.4%) in Saranac, extremely low estimates were obtained for IVDMD in both cultivars (7.9% for Saranac and 6.1% for MSA‐C4). Heritabilities for the remaining characters wcre intermediate (22.0 to 33.8%). In breeding for improved nutritive value of alfalfa, selection for greater protein content or reduced ADF, NDF, or lignin content would be recommended over selection for greater IVDMD.Estimates of genotypic, phenotypic, and environmental correlations indicated that: (1) Yield was not strongly correlated with any of the quality parameters; (2) ADF, NDF, and lignin were positively correlated with each other and negatively correlated with IVDMD and protein; and (3) IVDMD and IVCWD were positively correlated. Althongh seldom significant, most of the correlations for mineral concentration with yield, ADF, NDF, and lignin in Saranac were negative. Protein content was positively correlated with P concentration; ADF was negatively correlated with Ca, Mg, and Fe concentrations; and lignin was negatively correlated with K concentration.