Biometrics for Plant Sciences

PlSci 547

Take Home Questions #2

Answers due by Wednesday 28, 2007, @ 9:30am

Answer all 4 questions

A total of 350 points are available

All answers should be typed

Grade points from each question are shown in bold square parenthesis

Late return of answers will be penalized by 10% per day late Unless a late return has been previously agreed 1. Prince Charlie of Never Never Land has been a greenie for many years. As such he has an interest in growing Brassica oilseed crops (canola, oriental mustard and yellow mustard) for biodiesel production to fuel his humungous cars. He has heard that the seed meal (residue after the oil is pressed out) has allelopathic effects on soil pests and could be used as a biopesticide in organic production. His greatest pest problems in organic vegetable production (cabbage, carrot, beans and pea) are nematodes and weeds. Design one or more suitable experiments to be carried out on his Duchy of Cornwell estate to determine which of the three seed meals would have greatest efficacy against weeds and nematodes and determine the appropriate application rate necessary for control of either and both pests. Indicate in your answer the land needed along with any equipment you’ll need to complete the study. (Hint: the seed meal is 8% nitrogen). [80 points].

2. Potatoes stored at low temperatures (35-360 F) accumulate reducing sugars, fructose and glucose that cause dark French fries when they are fries. Potatoes stored at higher temperatures (<500F) do not accumulate sugars nearly as fast. Greater reducing sugar accumulation is associated with longer periods of storage. A new potato cultivar has been released (‘Brodick’) that has genes that do not accumulate sugars as fast as previous cultivars (mainly ‘Russet Burbank’). In addition it is know that increased nitrogen can cause greater sugar accumulation than lower level, however, lower nitrogen is associated with lower yield and smaller tubers. Design one or more experiments to examine the effects of nitrogen and storage temperature over time on yield, tuber size and fry quality. You are to complete this experiment on irrigated lands with solid set sprinkler systems set 30 feet apart and each capable of applying nitrogen with irrigation and each can be set at different nitrogen rates. You also have at your disposal four storage units with variable temperature control. Potatoes are planted into ridges 30 inches apart. In your answer outline the designs used along with land use, data that is to be collected and at which stage. [90 points].

3. Oriental mustard (Brassica juncea) is a new crop to the dry land Pacific Northwest growers. As a result, there is little information regarding the effects of broadleaf and grassy weeds nor the competitiveness of Oriental mustard compared to other Brassica crops grown in the region (canola, B. napus and rapeseed, B. rapa). Design one or more experiment to examine this question. You have an area of ground 200 x 200 feet in which to complete this study. You also know that there are two herbicides labeled for use in these crops, Treflan, applied pre-plant incorporated that controls broadleaf weeds, and Assure II, spray application post emergence, that controls grassy weeds. Design one or more experiment to examine yield loss due to broadleaf and grassy weeds and determine whether Oriental mustard is more or less competitive with weeds compared to the other two Brassica crops. Indicate all equipment you will need to complete this study and indicate all data that you intend to collect throughout the study. [90 points].

4. The yield of five cultivars (A, B, C, D and E) from a 5x5 Latin square is presented below. Determine the effect of each factor in the design model and hence indicate whether the Latin square design would have been the ‘best’ design to use in this situation. [40 points]

Column Row 1 2 3 4 5 1 A – 100 B – 86 E – 15 D – 153 C – 50 2 C – 32 D – 134 A – 110 B – 92 E – 20 3 D – 126 A – 105 C – 41 E - 18 B – 93 4 E – 8 C – 35 B – 88 A – 117 D – 162 5 B – 85 E – 12 D – 146 C – 45 A – 121

5. Photo period and temperature are key factors that need to be controlled to successfully produce haploid plants through embryogenesis of Brassica napus L. Past research shows that greatest success is attained when largest flower buds are harvested (16 h day and 8 h night with 65oF day and 50oF night). So far no research has been done in embryogenesis of Sinapis alba L. (yellow mustard). You have been asked to design an experiment to determine whether these are the optimum condition that will result in largest flower buds of S. alba. You have at your disposal four growth rooms with variable day length and temperature control. Each growth room is 4 x 5 feet. Pot sizes available are 6, 12 or 18 inch diameter. Design a suitable experiment to determine the optimal growing conditions for largest buds in S. alba. [50 points].