Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Combining all desirable character in a single cultivar of mango is difficult
Reason (R) : Mango is a homogeneous crop of suspected diploid origin
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Mango breeding is tough because:
It's highly heterozygous (genetically diverse).
It's polyploid (complex genetics, likely from diploid ancestors).
It has a long time to fruit. "Homogeneous crop" in (R) likely refers to individual cultivars being clones. These genetic complexities explain why combining many good traits (A) is hard.

Answer 1

The Correct Option is A

Assertion (A): Combining all desirable characters in a single cultivar of mango is difficult. This statement is true. Mango breeding is known to be very challenging. Desirable traits like high yield, excellent fruit quality (flavor, color, fiber content), disease/pest resistance, and regular bearing are often controlled by multiple genes. Mango also has a long juvenile period (time to first fruiting), is highly heterozygous (genetically diverse within an individual), and is often cross-pollinated, making it hard to fix and combine many good traits into one variety. Reason (R): Mango is a homogeneous crop of suspected diploid origin. Let's break down this statement:
"Suspected diploid origin": Cultivated mango (Mangifera indica) is generally considered an allotetraploid (4 sets of chromosomes, 2n=4x=40), likely originating from diploid ancestors. So, this part is plausible in an evolutionary sense.
"Homogeneous crop": This part needs careful interpretation. While the overall species Mangifera indica is highly diverse, individual commercial mango cultivars are vegetatively propagated (clones). This means each tree of a specific cultivar (e.g., 'Alphonso') is genetically identical, i.e., "homogeneous" within that cultivar. If "crop" refers to these elite clonal cultivars, then they represent specific, fixed (homogeneous) genetic combinations. Assuming "homogeneous crop" refers to the genetic uniformity *within* established clonal cultivars and acknowledging its polyploid nature derived from diploid ancestors, (R) can be considered true in this context. Is (R) the correct explanation of (A)? The difficulty in combining traits (A) is indeed related to mango's genetic nature (R).
Its (suspected) diploid origin leading to a more complex polyploid state (allotetraploidy) means genetic segregation during breeding is complicated, making it hard to predict offspring traits and combine genes effectively.
The "homogeneous" nature of existing elite clonal cultivars means that while they have some desirable traits fixed, introducing new traits from other diverse (heterozygous) parents and then re-stabilizing all desired traits is a significant challenge due to the complex genetics and long breeding cycle. Breaking existing linkages or undesirable gene combinations while retaining all good ones in a polyploid is difficult. Thus, the complex genetic makeup (polyploid from diploid ancestors, high heterozygosity) and the way desirable traits are often fixed within specific clonal lines (homogeneous cultivars) contribute to the difficulty of combining all desirable characters into a new single cultivar. So, both (A) and (R) are true, and (R) provides a valid underlying genetic reason for (A). Both (A) and (R) are true and (R) is the correct explanation of (A).