Three trials were conducted in 2006/07 and 2007/08 growing seasons aiming to find the effect of genotype, crop and weed population densities, herbicide, and sowing date on crop growth and yield in Pisum sativum as influenced by radiation interception and utilisation. The first experiment was a split plot with two cyanazine treatments as main plots. Subplots were a factorial combination of three pea genotypes and three plant population densities. Experiment 2 was also a split plot with three sowing dates as main plots. Sub-plots were a factorial combination of two pea genotypes, and two herbicide treatments. Experiment 3 treatments were a factorial combination of four pea populations and three sown artificial weed population densities arranged in a randomised complete block. Each of the three experiments had three replicates. Dry matter and radiation were measured throughout the growing season and seed yield was measured at harvest. There were significant (p = 0.05) herbicide by population interactions on total dry matter (TDM) and seed yield. Early pea sowing was associated with greater total radiation accumulation. The August sowing gave the highest seed yield 547 g m-2, which was 45% more than the lowest yield in October. The higher yield was a result of increased accumulative radiation interception. Increased pea population density increased yield. However, very high density (400 plants m-2) resulted in reduced seed yield.

The effects of individual climatic elements on crop growth during distinct phases of plant development can be quantified allowing the calibration of mechanistic numerical models of crop growth. Such models give greater understanding of how different climatic factors interact to determine crop yield and have several uses including the prediction of where previously untested crops might be grown and of how changes in climate in specific regions could affect crop growth and yield there. In this chapter, we focus on lentil (Lens culinaris). Firstly, we describe LENMOD a lentil crop growth model developed in Canterbury, New Zealand (NZ). Secondly, we give details of a case study of validation of the model in the United Kingdom (UK) and its use to predict crop growth and seed yield of spring and autumn sown lentils in eight sites along a transect from NW Scotland to SE England chosen to encompass important environmental gradients in the UK. Finally, we use LENMOD to predict the likely effects of increased temperature and increased soil moisture deficits (the two most likely long-term effects of climate change in Canterbury, NZ) on lentil growth and yield in Canterbury, NZ.It is concluded that lentil has considerable potential as a grain legume crop in the UK while yields of lentil in NZ are likely to increase slightly in response to predicted climate change.

Field experiments were conducted in 1995/96 and 1996/97 to investigate the effect of early blight epidemics on photosynthetically active radiation (PAR) interception (RI), radiation use efficiency (RUE), and total dry matter (TDM) production of potatoes (Solanum tuberosum) grown in Canterbury, New Zealand. RI was calculated from green leaf area index (GLAI) corrected for disease. RUE was calculated as the ratio between accumulated TDM and accumulated RI. Early blight reduced RI by 9% in both seasons and RUE by 17% and 28% in 1995/96 and 1996/97 respectively. There was a total loss of 26% and 36% in TDM in 1995/96 and 1996/97 respectively. Nitrogen inputs increased RUE by 3% and 16% as compared to low nitrogen status in 1995/96 and 1996/97 respectively. Results showed that RI and RUE, calculated from leaf area index (LAI), not corrected for disease, underestimated the loss in RI and RUE.

Legume inoculation is an established agricultural practice which has contributed to increased N-2 fixation and yield. Despite this evidence there is still an ongoing debate as to whether inoculation is necessary in grain legume production. Over the period 2003-05 a series of field experiments were conducted at Lincoln University, Canterbury, New Zealand to evaluate the effect of inoculation on common bean (Phaseolus vulgaris L.) production. Two white seeded bean cultivars, Scylla and T-49, were inoculated with six strains of Rhizobium phaseoli Dangeard, CC 511, RCR 3644, UK 2, H 20, PRF 81 and PhP 17 to determine their nodulation capabilities.Nodulation was variable and appeared to be affected by cultivar and Rhizobium strain. The two planting areas used, which had similar cropping histories, gave contrasting results. In the first season (Paddock 1), when a peat based inoculum was used, no nodulation was observed. In the second season (Paddock 2) liquid inoculum was used and nodulation ranged form 0 to 7.3 nodules plant(-1) at 21 days after sowing (DAS) to 0 to 75 nodules plant(-1) at 70 DAS. Cultivar also significantly affected the number of nodules plant(-1); ranging between 2-5 nodules plant(-1) at 21 DAS to 18-19 nodules plant(-1) at 70 DAS.Shoot dry matter (DM) over the two growing seasons ranged from 370-894 g m(-2), while green pod yield (taken at an average green seed length of I I mm) ranged from 138 to 471 g m(-2). Total DM at final harvest ranged from 530 to 1, 180 g m(-2) and seed yield ranged from 266 to 635 g m(-2). Strains H 20 and PRF 81 consistently out performed the other strains in most measured parameters. The results confirm the difficulty of predicting nodulation, and question the benefits of inoculating Phaseolus beans in Canterbury.

Most soils sown to common beans (Phaseolus vulgaris L.) contain indigenous Rhizobium phaseoli Dangeard, thus it is necessary to evaluate new strains of R. phaseoli. In 2004-2005 the effect of five strains of R. phaseoli on two cultivars of beans was investigated at Lincoln University. The cultivars Scylla and T-49 were inoculated with liquid cultures of strains RCR 3644, UK 2, H 20, PRF 81 and PhP 17 to determine their effect on nodulation, growth and yield. Nodulation was variable among strains. Over the sampling period T-49 consistently had higher nodule numbers/plant ranging from 4.74 at 21 days after inoculation (DAI) to 20.6 at 54 DAI. In Scylla the range was 1.42 at 21 DAI to 17.5 at 70 DAI. Strain H 20 gave the highest number of nodules/plant in both bean cultivars and this was associated with the highest green pod yield/m 2 in Scylla. Scylla, with strain PRF 81 gave the highest overall shoot dry matter (DM) yield of 692 g/m 2 . This gave a green pod DM yield of 202.3 g/m 2 . In contrast, PRF 81 on T-49, which produced the second most nodules, gave a shoot DM yield of 521 g/m 2 and a green pod DM yield of 225.5 g/m 2 . Strains H 20 and PRF 81 gave the best green pod yield in both bean cultivars. Scylla gave the highest shoot DM/m 2 with H 20 and PRF 81. In T-49, PRF 81 and PhP 17 produced shoot DM yields of 225.5 and 192.7 g/m 2 respectively. The results indicate that it should be possible to increase nodulation and yield of common beans in Canterbury by combining suitable bean cultivars with an appropriate strain of rhizobia.

Infection of grapevines by Phaeoacremonium species, thought to cause young vine decline, is currently causing concern to grape growers worldwide.Symptoms of the disease include chlorotic, sparse and stunted leaves, late bud-burst, uneven growth and undersized trunks, which show internal discolourations and frequently exude shiny, black, tarry substances ('black goo').This study investigated prevalence of the disease within commercial vineyards in selected grape-growing areas.Grape growers, largely from Marlborough but also from Nelson, Canterbury and Gisborne, contributed vines with decline symptoms for further observation and isolation.Characteristic internal staining of vine trunks was found, usually below the graft union, in 84% of the 70 vine samples.Isolations onto selective agar found Phaeoacremonium spp., most commonly P. chlamydosporum, in 54% of vines and in 20 of the 27 vineyards sampled.Incidence may have been higher but 26% of wood specimens also contained other, fast-growing fungi which overgrew the wood tissues, interfering with attempts to isolate the slowgrowing Phaeoacremonium spp.Isolations from roots of the 33 most severely infected vines found 14 to be also infected with Cylindrocarpon destructans, which causes a root rot called 'black foot'.Further studies are needed into young vine decline and into the epidemiology and control of P. chlamydosporum.

The effects of a range of applied nitrate (NO3-) concentrations (0-20 mol m-3) on germination and emergence percentage of Triticum aestivum L. cv. Otane were examined at 30, 60, 90 and 120 mm sowing depths. Germination percentage was not affected by either sowing depth or applied NO3- concentration whereas emergence percentage decreased with increased sowing depth regardless of applied NO3- concentration. Nitrate did not affect emergence percentage at 30 mm sowing depth, but at 60 to 120 mm depth, emergence percentage decreased sharply with an increased applied NO3- concentration of 0 to 1.0 mol m-3 then decreased only slightly with further increases in applied NO3- of about 5.0 mol m-3.Root and shoot growth, NO3- accumulation and nitrate reductase activity (NRA) of plants supplied with 0, 1.0 and 10 mol m-3 NO3- at a sowing depth of 60 mm were measured prior to emergence. The coleoptile of all seedlings opened within the substrate. Prior to emergence from the substrate, shoot extension growth was unaffected by additional NO3- but shoot fr. wt. and dry wt. were both greater at 1.0 and 10 mol m-3 NO3- than with zero NO3-. Root dry wt. was unaffected by NO3-. Nitrate concentration and NRA in root and shoot were always low without NO3-. At 1.0 and 10 mol m-3 NO3-, NO3- accumulated in the root and shoot to concentrations substantially greater than that applied and caused the induction of NRA. Regardless of the applied NO3- concentration, seedlings which failed to emerge still had substantial seed reserves one month after planting. Coleoptile length was substantially less for seedlings which did not emerge than for seedlings which emerged, but was not affected by NO3-. It is proposed that (a) decreased emergence percentage with increased sowing depth was due to the emergence of leaf 1 from the coleoptile within the substrate and (b) decreased emergence percentage with additional NO3- was due to the increased expansion of leaf 1 within the substrate resulting in greater folding and damage of the leaf.