Plant Genetics and Pathology Quiz

What is one potential consequence of decreasing genetic diversity within the population of crops?

• Improved nutritional content

• Greater susceptibility to diseases and pests

• Enhanced resilience

• Increased adaptability

As a plant pathologist, how do you prove whether a given microorganism is causing disease or not? Please provide a step-by-step procedure.

Considering that tall rice variety exhibit high yield but is vulnerable to damage in windy conditions, while dwarf rice variety have a lower yield but better resilience to adverse weather, what outcomes would you expect from the crossbreeding of these two varieties? (1 pt). As a breeder, which variety would you designate as the pollen (male) parent, and which as the seed (mother) parent in this crossbreeding scenario (2 pts) and why? (1pt)

If a pea plant with the genotype Aa is crossed with another pea plant having the genotype aa, what percent of the offspring is expected to express the dominant phenotype?

• 75%

• 50%

• 25%

• 0%

Red bone marrow produces lymphocytes.

• True

• False

Benitus is hoping to grow a crop which is sensitive to day length. How can understanding the implications of photoperiod on plant growth and development assist Benitus in optimizing crop production?

• Regulate flowering time

• Adjust planting dates

• All of these

• Manage irrigation practice

• Improve soil structure

Which of the following is not the positive role of bacteria and fungi in conservation agriculture?

• Secrete enzymes in the soil to make phosphorus more soluble and plant available

• None of these

• Have the ability to increase nitrogen in the soil through the decomposition of organic matter

• Consuming nitrogen and converting it into protein

• Creating stable aggregates that help increase water infiltration and soil water holding capacity.

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

• None of these

• red × white

• red × roan

• white × roan

• roan × roan

Esther and Arsene observe that some leaves of a particular plant fold together at night but spread out during the day. What is this type of movement called, and which hormone is responsible for controlling this process?

• Phototropism; Gibberellin

• Thigmotropism; Auxin

• None of these

• Nyctinasty; Abscisic acid

• Hydrotropism; Cytokinin

Which of the following is not correctly matched?

• Abscisic acid----responding to environmental stresses

• None of these

• Gibberellin---- break seed dormancy

• Ethylene----fruit ripening and leaf abscission

• Cytokinin---- stimulates cell division and lateral bud growth