Select the incorrect statement from the following:

1) NBRI (National Botanical Research Institute) is situated at Lucknow

2) Plant families like convolvulaceae and solanaceae are included in other polynomials mainly based on floral characters

3) All living organisms – present, past and future are linked to one another by sharing of common genetic material but to varying degrees

4) Order solanum, datura and petunia are placed in the family solanaceae

To identify the incorrect statement, let's analyze each of the given statements one by one:

Statement 1: "NBRI (National Botanical Research Institute) is situated at Lucknow"
This statement is correct. The National Botanical Research Institute (NBRI) is a renowned research institute of the CSIR, located in Lucknow, Uttar Pradesh, India.

Statement 2: "Plant families like convolvulaceae and solanaceae are included in other polynomials mainly based on floral characters"
This statement contains a small typographical error common in biology databases (using "other polynomials" instead of the taxonomic order "Polymoniales"). In taxonomic classification, plant families like Convolvulaceae and Solanaceae are indeed grouped under the order Polymoniales, and this classification is primarily based on their floral characteristics. Thus, in the context of taxonomic principles, the underlying scientific fact is considered correct.

Statement 3: "All living organisms – present, past and future are linked to one another by sharing of common genetic material but to varying degrees"
This statement is correct. It is a fundamental concept of evolutionary biology. All living organisms share a common genetic material (DNA/RNA), which establishes their evolutionary connection, though the percentage of shared genetic code varies depending on how closely related the species are.

Statement 4: "Order solanum, datura and petunia are placed in the family solanaceae"
This statement is incorrect. Solanum, Datura, and Petunia are genera (plural of genus), not orders. They are genera that are placed under the family Solanaceae. The taxonomic hierarchy classifies these as genera, so calling them an "order" is taxonomically incorrect.

Since statement 4 is the only incorrect statement among the options, the correct option is "4 only".