Variations in Seed Production and the Response to Pests of Morningglory (Ipomoea) Species and Smallflower Morningglory (Jacquemontia tamnifolia)

Weed Science ◽  
1982 ◽  
Vol 30 (2) ◽  
pp. 187-190 ◽  
Author(s):  
R. Hugh Crowley ◽  
Gale A. Buchanan

Flowering dates, seed production, and disease and insect susceptibility of sevenIpomoeaspp. and smallflower morningglory [Jacquemontia tamnifolia(L.) Griseb.] were determined under field conditions in 1973 and 1974. Seed produced per plant were as follows: ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.], 6000; entireleaf morningglory [I. hederacea(L.) Jacq. var.integriusculaGray], 5000; pitted morningglory [I. lacunosaL.], 10000; wild tall morningglory [I. purpurea(L.) Roth.], 26000; commercial tall morningglory [I. purpurea(L.) Roth ‘Crimson Rambler′], 15 000; cypressvine morningglory (I. quamoclitL.), 9000; cotton morningglory [I. trichocarpaEll. var.torreyana(Gray) Shinners], 9000; palmleaf morningglory (I. wrightiiGray), 7000; and smallflower morningglory, 11000. Seed weights were about 29, 26, 22, 21, 19, 13, 19, 37, and 5 mg/seed, respectively. Pitted morningglory appeared to have a qualitative short day-length requirement for flower initiation and the other species appeared less day-length sensitive. Ivyleaf morningglory and entireleaf morningglory were highly susceptible to orange rust [Coleosporium ipomoeae(Schw.) Burrill] and white rust [Albugo ipomoea panduratae(Schw.) Swingle], but the otherIpomoeaspecies were only slightly susceptible and smallflower morningglory was resistant. Cotton bollworms (Heliothis zeaBoddie) and cabbage loopers (Trichoplusia niHubner) fed preferentially on ivyleaf morningglory and entireleaf morningglory.

Weed Science ◽  
1983 ◽  
Vol 31 (6) ◽  
pp. 837-840 ◽  
Author(s):  
Robert J. Thullen ◽  
Paul E. Keeley

In 1979 and 1980, ivyleaf morningglory [Ipomoea hederacea(L.) Jacq. # IPOHE] seed were planted in field plots at monthly intervals beginning with March and continuing through October. During the first 9 weeks, seedlings from the July plantings grew more rapidly than those from the other monthly plantings and produced the heaviest fresh weights. Vegetative growth slowed after the 9-week harvest and seedlings from June plantings had heavier fresh weights at the 12-week harvest. Plants from the July planting produced the greatest number of seed at both the 9- and 12-week harvests. After scarifying, seed produced by plants from April through August (12-week harvest) germinated best with the 27/32 C night/day air temperature regime, but also germinated at 15/21, 21/27, and 27/32 C regimes. Ivyleaf morningglory seed did not germinate at an air temperature regime of 10/15 C. With an air temperature regime of 32/38 C the germination of some lots began to decrease.


1989 ◽  
Vol 24 (2) ◽  
pp. 258-265 ◽  
Author(s):  
Loke-Tuck Kok ◽  
Thomas J. McAvoy

The major pests of fall broccoli in south-central Virginia between 1985/87 were Trichoplusia ni (Hübner), Hellula rogatalis (Hulst), Plutella xylostella (L.), and Heliothis zea (Boddie); minor pests included Pieris rapae (L.), Evergestis rimosalis (Gueneé), Spodoptera ornithogalli (Gueneé), Pieris protodice Boisduval and LaConte and Plathypena scabra F. Seven species of parasites were recovered, the most abundant being Diadegma insularis (Cresson) which parasitized up to 37% of the diamondback moth larvae and Cotesia marginiventris (Cresson) which parasitized up to 20% of the corn earworms. The other parasites were found in very low numbers.


1999 ◽  
Vol 13 (4) ◽  
pp. 791-798 ◽  
Author(s):  
David R. Shaw ◽  
Andrew C. Bennett ◽  
Donald L. Grant

Cloransulam postemergence (POST), diclosulam preemergence (PRE), and flumetsulam preplant incorporated (PPI) and POST were evaluated in six trials at two locations for control of sicklepod and pitted morningglory in soybean. Sicklepod control with cloransulam plus flumetsulam POST was equivalent to chlorimuron POST in seven of eight comparisons both 3 and 6 wk after treatment. Sicklepod control with cloransulam POST was equivalent to chlorimuron in only three of eight comparisons 3 wk after treatment, but late-season control was equivalent in five of six comparisons. Pitted morningglory control with cloransulam alone or in tank-mixture with flumetsulam POST was equivalent to chlorimuron in all comparisons. Control of sicklepod and pitted morningglory was greater in most comparisons when a POST application followed flumetsulam plus trifluralin PPI compared to only trifluralin PPI. In a total PRE stale seedbed system, where all treatments were tank-mixed with pendimethalin plus glyphosate, sicklepod control with all rates of flumetsulam and 26 or 35 g ai/ha diclosulam was equivalent to the standard treatment of imazaquin or metribuzin plus chlorimuron. None of the total PRE programs controlled sicklepod as well as when glyphosate was applied sequentially POST. Pitted morningglory was controlled 83 to 93% with 26 or 35 g/ha diclosulam, equivalent to imazaquin, metribuzin plus chlorimuron, or sequential glyphosate applications 8 wk after the PRE application. Increasing flumetsulam rate increased pitted morningglory control early season, but flumetsulam was not as effective as the other herbicides.


1976 ◽  
Vol 16 (79) ◽  
pp. 226 ◽  
Author(s):  
DS Loch ◽  
JM Hopkinson ◽  
BH English

The consequences of defoliation on seed production of stylo (Stylosanthes guyanensis) were examined in field experiments at Walkamin in north Queensland. The practical aim of defoliation is to present a level uncompacted crop canopy to the harvester without a reduction in the quantity of seed carried at harvest ripeness. It was concluded that the latest date at which defoliation is reasonably certain to achieve its objectives is about four weeks before first flower initiation. In north Queensland, this means late February for cvv. Cook and Endeavour and early April for cv. Schofield. The results suggest that development of the population of individual shoots must be synchronized to produce the highest peaks of standing seed; that this is best achieved by ensuring that a closed crop canopy with a ceiling shoot population exists at the time of first flower initiation; and that poorly synchronized shoot development is a consequence of defoliating too late and a cause of reduced seed production.


1967 ◽  
Vol 7 (29) ◽  
pp. 489 ◽  
Author(s):  
DF Cameron

The flowering of seven selections of Townsville lucerne (Stylosanthes humilis HBK) representing a range of maturity types has been studied in the Canberra phytotron. Daylength is the main factor controlling flowering in these selections, all of which showed a strong short day response. At normal temperatures the maximum daylengths at which all plants flowered (the critical daylengths) were 13 hours for the early, 12 hours for the midseason and late-midseason, and 11 1/2 hours for the late selections. However, the midseason selections did flower in a 12 1/2-hour daylength if the light intensity of the supplementary illumination was 20 or 5 ft.c. instead of the normal 50 ft.c. The response of the other selections was not altered at the lower light intensities. Both high night temperature and low day temperature delayed or inhibited flower initiation in the early and midseason selections and these effects were greater at a critical daylength.


1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.


Weed Science ◽  
1978 ◽  
Vol 26 (5) ◽  
pp. 484-488 ◽  
Author(s):  
R. H. Crowley ◽  
G. A. Buchanan

Tall morningglory [Ipomoea purpurea(L.) Roth.], pitted morningglory(I. lacunosaL.), ivyleaf morningglory [I. hederacea(L.) Jacq.] and entireleaf morningglory(I. hederaceavar.integruisculaGray) were compared for their competitive ability with cotton(Gossypium hirsutumL.) at weed densities of 4, 8, 16 and 32 weeds/15 m of row. Tall morningglory was the most competitive with yield reductions of as much as 88% at 32 weeds/15 m. The higher populations of tall morningglory also significantly reduced cotton populations, mechanical harvesting efficiency and lint percentage below that in the controls. Pitted morningglory densities twice that of tall morningglory were required to produce cotton responses similar to those induced by tall morningglory. Ivyleaf morningglory and entireleaf morningglory were almost identical in their competitive potentials and were less competitive than the other species evaluated. Their competitive ability was greatly reduced by disease. Competition from morningglories did not consistently affect cotton fiber micronaire, fiber length or strength.


1969 ◽  
Vol 17 (3) ◽  
pp. 375 ◽  
Author(s):  
LT Evans ◽  
RB Knox

Seedlings and older plants of 30 ecological races of Themeda australis were grown under controlled conditions to determine the effect of day length and vernalization on their flowering and on the incidence of apomixis. The races ranged in origin from latitude 6°S. in New Guinea to latitude 43°S, in Tasmania. One race from New Guinea and several from the Northern Territory behaved as strict short-day plants. The more southerly races, on the other hand, and several from north Queensland were long-day plants. In some, long days were required for both initiation and development of the inflorescence, in others apparently only for initiation. Some races required long days as seedlings, but not as older plants. Races from drier inland areas tended to be indifferent to day length in their flowering behaviour. At least four races from the colder areas responded to vernalization. Both the sexual and the aposporous reproductive pathways are described. Two races were wholly sexual in their breeding system and two appeared to be almost entirely aposporous, but most were versatile, displaying both sexual and aposporous reproductive behaviour. In seven races there was some evidence that day length influenced the reproductive pathway, short days causing increased apospory in all cases, regardless of the day length requirements for flowering.


2010 ◽  
Vol 278 (1714) ◽  
pp. 1989-1996 ◽  
Author(s):  
Jay M. Biernaskie

A plant's best strategy for acquiring resources may often depend on the identity of neighbours. Here, I ask whether plants adjust their strategy to local relatedness: individuals may cooperate (reduce competitiveness) with kin but compete relatively intensely with non-kin. In a greenhouse experiment with Ipomoea hederacea , neighbouring siblings from the same inbred line were relatively uniform in height; groups of mixed lines, however, were increasingly variable as their mean height increased. The reproductive yield of mixed and sibling groups was similar overall, but when adjusted to a common mean height and height inequality, the yield of mixed groups was significantly less. Where this difference in yield was most pronounced (among groups that varied most in height), mixed groups tended to allocate more mass to roots than comparable sibling groups, and overall, mixed groups produced significantly fewer seeds per unit mass of roots. These results suggest that, from the group perspective, non-kin may have wasted resources in below-ground competition at the expense of reproduction; kin groups, on the other hand, displayed the relative efficiency that is expected of reduced competitiveness.


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