Morphological Development of Alfalfa Cultivars Selected for Higher Quality

Abstract

Alfalfa (Medicago sativa L.) maturity at the time of harvest greatly influences forage quality. The objective of this research was to determine if observed quality differences between high quality and other alfalfa cultivars were due to differences in morphological development. Two high‐quality cultivars (‘WL 252HQ’, ‘WL 322HQ’) and two check cultivars (‘5262’, ‘5454’) with similar fall dormancy ratings were established on a Murrill silt loam (fine‐loamy, mixed, mesic Typic Hapludult) in the spring of 1996. During 1997, 1998, and 1999, each cultivar was hand‐sampled weekly for 4 consecutive wk during the spring growth period and for 3 consecutive wk during the three subsequent growth periods. Morphological development and forage quality were determined for each alfalfa cultivar at each sampling. There were no interactions between growth period or sampling times and alfalfa cultivars for either alfalfa maturity or forage quality. Morphological development of the cultivars was not different at any of the sampling times. Averaged across all growth periods and sampling times, crude protein (CP) concentrations and in vitro dry matter digestibility (IVDMD) were 14 and 13 g kg−1, respectively, higher for the high‐quality cultivars (ADF) and neutral‐detergent fiber (NDF) concentrations were 16 and 15 g kg−1, respectively, lower. The data from this research indicates that the difference in quality between the high quality and traditional alfalfa cultivars is not due to differences in morphological development. Selecting for higher‐quality alfalfa was successful and is not an artifact of inadvertently selecting for delayed development.

Estimation of red clover (Trifolium pratense L.) forage quality parameters dependingon the variety, cut and growing year

“…However, Sheaffer et al (1998) indicated on the basis of their experiment that ranking of alfalfa entries for forage quality was more affected by season than by either location or maturity of the alfalfa. Also Hall et al (2000) found no connection between growth period or sampling time and forage quality at alfalfa cultivars. The findings of their research indicated that the difference in quality between the high quality and traditional alfalfa cultivars was not due to differences in morphological development.…”

“…Hall et al (2000) reported that the non-significant interaction between the alfalfa cultivars and growth periods indicates that the higher forage quality of high-quality cultivars is a stable phenotypic trait throughout the growing season.…”

Achievements and Challenges in Improving Temperate Perennial Forage Legumes

“…The information summarized in Table 1 suggests that no overall variation for forage digestibility and contents of protein and neutral detergent fiber (NDF, associated with rate of forage ingestion by animals) has arisen from alfalfa breeding. However, successful selection for all of these traits has been performed and made available by specific "high-quality" alfalfa cultivars (Hall et al, 2000).…”

“…On the other hand, narrow-sense heritability values for these traits are reportedly modest, ranging from 0.18 to 0.39 (Guines et al, 2002). Selection for improved quality has produced varieties with consistently greater digestibility and protein content and lower NDF (Hall et al, 2000). The development of increasingly reliable near-infrared reflectance spectroscopy (NIRS)-based estimation has made possible and cost-effective the evaluation of many plants or families in breeding programs.…”

Impact of Long‐Term Phosphorus and Potassium Fertilization on Alfalfa Nutritive Value–Yield Relationships

“…In a 4-yr study, Hall et al (2000) found greater crude protein (CP) and in vitro true dry matter disappearance (IVTDMD) and less neutral detergent fi ber (NDF) and acid detergent fi ber (ADF) in the fourth production year compared with the second and third production years. Reduced productivity with stand age can alter forage quality.…”