Indian ricegrass [Olyzopsis hy#nt?noties (Roem. and Schuit.) Ricker] is an excellent native species for revegetation of coal and oil shale sites. However, inadequate germination due to a high seed dormancy results in poor stand development and limits its use. This paper presents the results of a series of experiments attempting to reduce the dormancy by weakening the lemma and paiea by scarification of the seed covering. Four treatments (three mechanical nnd one concentrated sulfuric acid) were examined, alone and in combination with gibberellic acid. Three ages of seed were tested in the greenhouse, the laboratory and the field. Concentrated sulfuric acid and a modified commercial scarifier most effectively increased germination in the greenhouse; gibbereilic acid enhanced germination of the younger, fresher seeds in this environment. A rubbing machine improved emergence in the tieid more than the other treatments. It was, however, only a modest improvement. Concentrated sulfuric acid decreased field emergence for ail 3 ages of seed. Germination studies in the laboratory indicated that none of the treatments increased mortality.

No abstract

Blue grama [Bouteloua grads (H.B.K.) Lag. ex Steud.] has been diicult to establish from seed on disturbed areas of the Central Plains. The objective of this study was to investigate the relationship of caryopsis weight, planting depth, and genetic variability on seedling emergence of blue grama. Two experiments were conducted in the greenhouse under favorable moisture conditions with 3 accessions and various combinations of caryopsis weight and planting depth. Measurements included rate of germination and emergence as an index, percentage emergence, shoot length, shoot weight, seminal root length, coleoptile length, subcoleoptile internode length and weight, adventitious root weight, and longest adventitious root length. The length of the subcoleoptile internode increased in response to greater planting depth but weight per unit length deereased. If this indicates a decrease in internode diameter it could decrease the rate of water transport through the internode. Deep plantings were not advantageous to emergence or seedling growth under favorable soil moisture conditions and caused a delay in emergence and decreased percentage emergence, shoot weight, and adventitious root weight. High crryopsisweight was associated with an increase in emergence, weight per unit length of the subcoleoptile internode, coleoptile length, shoot weight, and adventitious root weight. Therefore, high caryopsis weight is advantageous in the deep plnnting of blue grama seeds and allows seeds to be planted deeper to take advantage of moisture for germination and emergence.

No abstract

Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] has been of interest for revegetation of western mine lands, however, high seed dormancy restricts stand establishment. Breeding to improve Indian ricegrass is hampered by this inherent dormancy, often as high as 98%. Scarification to break dormancy using sulfuric acid has been successful but reduction of viability has occurred. This study examined whether the number of seeds damaged by scarification was related to the thickness of the indurate lemma possessed by Indian ricegrass. Twelve strains and cultivars of Indian ricegrass were examined with a range in lemma thickness of 42 to 76 μm. They differed significantly for this trait, which was not affected by environment. Acid scarification treatments of 20, 30, and 40 rain were followed by water rinses. Viability before and after scarification was determined by tetrazolium tests. Lemma thickness had a significant protectiveffect on seed viability after scarification for all three scarification durations. Coefficients of determination (R2) values were 0.56, 0.75, and 0.79 for 20, 30, and 40 min time, respectively. These results indicate that lemma thickness can be utilized to determine proper scarification duration to minimize seed damage while maximizing germination, resulting in uniform stand establishment and evaluation of Indian ricegrass germplasm.

High caryopsis weight in forage plants generally increases seedling emergence, vigor, and establishment. Breeding for improved caryopsis weight in blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.] can be successful only if variations in average caryopsis weight of a plant are not simply a result of variations in the components of caryopsis yield. The objectives of this study were to determine the effects of spikes/culm, spikelets/spike, and fertility on caryopsis weight and the effects of spikes/culm, spikelets/spike, fertility, and caryopsis weight on yield/culm. In a 1,080−plant, spaced field nursery, average caryopsis weight varied among plants from 25 to 70 mg/100. Multiple regression and path analysis indicated that spikes/culm, spikelets/spike, and fertility accounted for only 5% of the variation in caryopsis weight. These components of yield, with caryopsis weight, accounted for 86% of the variation in caryopsis yield/culm. In a polycross nursery of 60 plants selected from the previous nursery primarily for high caryopsis weight, blue grama clones differed significantly in all of the components of caryopsis yield/culm. Blocks in the polycross nursery differed significantly in all components of yield/culm except average caryopsis weight of a plant. These results suggest that it would be possible to select blue grama plants for both high caryopsis weight and high seed yields.

Lupila88repioneeringpinm8ny dbhrbed mount8in lmbi-t8tr in Color8do. The purpo8c of thb work wu to determine if Lupinus qenteus, L. cad&us, and L. a&a&& could be useful revegewion pl8ntN in 8 recl8m8tion proglmm. P8ired roil s8mple8 from 33 dbtwbed sitea supporting 118th lupine8 were used to determine if lupines incrwcd the nitrogen content of the soil. Soil urnplea collected 10 cm from lupiae t8p roots 8ver8ged 13.8 mg kc' more excb8ngerble ullmonium 8nd 2.7 mg kr1 more nhte tb8n soil mmpks collected 3 m from lupine phnts. Field mcrrured 8cetylene reduction ntea of dehched lupine nod&s 8venged 10.0 pmol ethylene rl nodule dry weight b-1 for L. urge&us ,and 17.3 pmol ethylene tl noduk dry weight b-1 for L. a~sfr&. Soil rdj8cent to lupines lmd higher kveb of inorg8nic nitrogen tb8n soila 3 m from lupine pl8nt118nd lupines b8d tbe rbility for biologhl llihgell dX8th 86 SbOWIl by the 8Cetyhe redllcth 8#88y, Wl_ gesting tbrt n8tive lupines 8re potentirlly useful reveget8tion phnts in 8 rechm8tion progr8m.

Blue grama [Boute~ouugrociris(H.B.K.) Lag. ex Steud.] has not been able to establish itself, or to be successfully planted, from seed on abandoned croplands of the Central Plains. The objectives of this study were to test blue grama phmt material under limited moisture and develop methods for improving emergence and establishment of blue grama seedlings. Experiments were conducted in the greenhouse and at the Central Plains Experimental Range near NUM, Colorado, with 3 accessions. Under limited moisture conditions in the greenhouse, seedlings emerged better from planting depths of 2.0 and 2.5 cm than from depths of 0.5,l.O or 1.5 cm. Higher caryopsis weight was associated with a significant increase in percentage emergence at all planting depths. Accession PM-K-1483 had greatest emergence, followed by 'Hachita' and 'Lovington'. Under favorable soil moisture conditions in the field (2 cm of water applied at planting dates in June and July 1981), deep planting resulted in decreased emergence. Averaged over all planting depths, percentage emergence increased nearly 2-fold with an increase in caryopsis weight from 39 to 59 mg/lOO. When soil moisture conditions were marginal (only 1 cm water added), satisfactory emergence was obtained only when highweight seeds were planted at a depth of 2 cm. Soil at a planting depth of 1 cm dried quickly and prevented emergence. Genetic improvement of caryopsis weight combined with planting at depths of about 2.0 cm should improve the emergence and establishment of blue grama seedlings.